MassGIS had received quarterly updates of these data as part of its license for the HERE (Navteq) core map release (streets and related data); however, that license has expired. These ZIP Code boundaries are aligned to the street centerlines of the Q2 2018 HERE product (with a release date of April 1, 2018) and use a then-recent USPS source file.In March 2024, MassGIS modified the boundaries for all ZIP Code areas in Boston based on the U.S. Postal Service's ZIP Code Look Up by Address website. MassGIS also added polygons for ZIP Codes 02199 and 02203.Five-digit ZIP Codes were developed by the USPS and first introduced in 1963 for efficient mail delivery (the term ZIP stands for Zone Improvement Plan) but are difficult to map with complete certainty. In most cases, addresses in close proximity to each other are grouped in the same ZIP Code, which gives the appearance that ZIP Codes are defined by a clear geographic boundary. However, even when ZIP Codes appear to be geographically grouped, a clear ZIP Code boundary cannot always be drawn because ZIP Codes are only assigned to a point of delivery and not the spaces between delivery points. In areas without a regular postal route or no mail delivery, ZIP Codes may not be defined or have unclear boundaries.The USPS does not maintain an official ZIP Code map. The Census Bureau and many other commercial services will interpolate the data to create polygons to represent the approximate area covered by a ZIP code, but none of these maps are official or entirely accurate. Please see this good discussion of the issues of mapping ZIP Codes.See full metadata.Map service also available.
https://en.wikipedia.org/wiki/Public_domainhttps://en.wikipedia.org/wiki/Public_domain
This dataset is part of the Geographical repository maintained by Opendatasoft.This dataset contains data for zip codes 5 digits in United States of America.ZIP Code Tabulation Areas (ZCTAs) are approximate area representations of U.S. Postal Service (USPS) ZIP Code service areas that the Census Bureau creates to present statistical data for each decennial census. The Census Bureau delineates ZCTA boundaries for the United States, Puerto Rico, American Samoa, Guam, the Commonwealth of the Northern Mariana Islands, and the U.S. Virgin Islands once each decade following the decennial census. Data users should not use ZCTAs to identify the official USPS ZIP Code for mail delivery. The USPS makes periodic changes to ZIP Codes to support more efficient mail delivery.Processors and tools are using this data.EnhancementsAdd ISO 3166-3 codes.Simplify geometries to provide better performance across the services.Add administrative hierarchy.
This feature service is derived from the Esri "United States Zip Code Boundaries" layer, queried to only CA data.For the original data see: https://esri.maps.arcgis.com/home/item.html?id=5f31109b46d541da86119bd4cf213848Published by the California Department of Technology Geographic Information Services Team.The GIS Team can be reached at ODSdataservices@state.ca.gov.U.S. ZIP Code Boundaries represents five-digit ZIP Code areas used by the U.S. Postal Service to deliver mail more effectively. The first digit of a five-digit ZIP Code divides the United States into 10 large groups of states (or equivalent areas) numbered from 0 in the Northeast to 9 in the far West. Within these areas, each state is divided into an average of 10 smaller geographical areas, identified by the second and third digits. These digits, in conjunction with the first digit, represent a Sectional Center Facility (SCF) or a mail processing facility area. The fourth and fifth digits identify a post office, station, branch or local delivery area.As of the time this layer was published, in January 2025, Esri's boundaries are sourced from TomTom (June 2024) and the 2023 population estimates are from Esri Demographics. Esri updates its layer annually and those changes will immediately be reflected in this layer. Note that, because this layer passes through Esri's data, if you want to know the true date of the underlying data, click through to Esri's original source data and look at their metadata for more information on updates.Cautions about using Zip Code boundary dataZip code boundaries have three characteristics you should be aware of before using them:Zip code boundaries change, in ways small and large - these are not a stable analysis unit. Data you received keyed to zip codes may have used an earlier and very different boundary for your zip codes of interest.Historically, the United States Postal Service has not published zip code boundaries, and instead, boundary datasets are compiled by third party vendors from address data. That means that the boundary data are not authoritative, and any data you have keyed to zip codes may use a different, vendor-specific method for generating boundaries from the data here.Zip codes are designed to optimize mail delivery, not social, environmental, or demographic characteristics. Analysis using zip codes is subject to create issues with the Modifiable Areal Unit Problem that will bias any results because your units of analysis aren't designed for the data being studied.As of early 2025, USPS appears to be in the process of releasing boundaries, which will at least provide an authoritative source, but because of the other factors above, we do not recommend these boundaries for many use cases. If you are using these for anything other than mailing purposes, we recommend reconsideration. We provide the boundaries as a convenience, knowing people are looking for them, in order to ensure that up-to-date boundaries are available.
This layer represents ZIP Code outlines for the state of North Carolina. The counties are stored as polygons.
A ZIP Code is a five digit numeric code that identifies a collection of mailing addresses within the United States and its territories to simplify the distribution of mail by the United States Postal Service (USPS).
A ZIP Code is a delivery sort sequence and the USPS does not associate an area with each ZIP Code. Said another way, ZIP Codes are lists of addresses for delivering the mail. They are not areas. However, many ZIP Codes have delivery areas, and some ZIP Codes are for buildings or campuses that have defined borders. Boundaries can also be created by grouping small areas (defined by the U.S. Bureau of the Census for their nationwide street map) based on the dominant ZIP Code of the addresses in each small area, but this is an approximation because carrier routes may overlap and portions of the country have no deliverable addresses. The ZIP Code areas often do not adhere to boundaries of cities, towns, counties, or states.
The 2019 cartographic boundary shapefiles are simplified representations of selected geographic areas from the U.S. Census Bureau's Master Address File / Topologically Integrated Geographic Encoding and Referencing (MAF/TIGER) Database (MTDB). These boundary files are specifically designed for small-scale thematic mapping. When possible, generalization is performed with the intent to maintain the hierarchical relationships among geographies and to maintain the alignment of geographies within a file set for a given year. Geographic areas may not align with the same areas from another year. Some geographies are available as nation-based files while others are available only as state-based files. ZIP Code Tabulation Areas (ZCTAs) are approximate area representations of U.S. Postal Service (USPS) ZIP Code service areas that the Census Bureau creates to present statistical data for each decennial census. The Census Bureau delineates ZCTA boundaries for the United States, Puerto Rico, American Samoa, Guam, the Commonwealth of the Northern Mariana Islands, and the U.S. Virgin Islands once each decade following the decennial census. Data users should not use ZCTAs to identify the official USPS ZIP Code for mail delivery. The USPS makes periodic changes to ZIP Codes to support more efficient mail delivery. The Census Bureau uses tabulation blocks as the basis for defining each ZCTA. Tabulation blocks are assigned to a ZCTA based on the most frequently occurring ZIP Code for the addresses contained within that block. The most frequently occurring ZIP Code also becomes the five-digit numeric code of the ZCTA. These codes may contain leading zeros. Blocks that do not contain addresses but are surrounded by a single ZCTA (enclaves) are assigned to the surrounding ZCTA. Because the Census Bureau only uses the most frequently occurring ZIP Code to assign blocks, a ZCTA may not exist for every USPS ZIP Code. Some ZIP Codes may not have a matching ZCTA because too few addresses were associated with the specific ZIP Code or the ZIP Code was not the most frequently occurring ZIP Code within any of the blocks where it exists. The generalized ZCTA boundaries in this file are based on those delineated following the 2010 Census.
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Census ZIP Code Tabulation AreasThis feature layer, utilizing National Geospatial Data Asset (NGDA) data from the U.S. Census Bureau, displays ZIP Code Tabulation Areas in the United States. Per the USCB, “ZIP Code Tabulation Areas (ZCTAs) are approximate area representations of U.S. Postal Service (USPS) ZIP Code service areas that the Census Bureau creates to present statistical data for each decennial census. Data users should not use ZCTAs to identify the official USPS ZIP Code for mail delivery. The USPS makes periodic changes to ZIP Codes to support more efficient mail delivery.”Tabulation Area: 90069Data currency: This cached Esri federal service is checked weekly for updates from its enterprise federal source (ZIP Code Tabulation Areas) and will support mapping, analysis, data exports and OGC API – Feature access.NGDAID: 58 (Series Information for 2020 Census 5-Digit ZIP Code Tabulation Area (ZCTA5) National TIGER/Line Shapefiles, Current)OGC API Features Link: (Census ZIP Code Tabulation Areas - OGC Features) copy this link to embed it in OGC Compliant viewersFor more information, please visit: ZIP Code Tabulation Areas (ZCTAs)For feedback please contact: Esri_US_Federal_Data@esri.comThumbnail source: Esri BasemapsNGDA Data SetThis data set is part of the NGDA Governmental Units, and Administrative and Statistical Boundaries Theme Community. Per the Federal Geospatial Data Committee (FGDC), this theme is defined as the "boundaries that delineate geographic areas for uses such as governance and the general provision of services (e.g., states, American Indian reservations, counties, cities, towns, etc.), administration and/or for a specific purpose (e.g., congressional districts, school districts, fire districts, Alaska Native Regional Corporations, etc.), and/or provision of statistical data (census tracts, census blocks, metropolitan and micropolitan statistical areas, etc.). Boundaries for these various types of geographic areas are either defined through a documented legal description or through criteria and guidelines. Other boundaries may include international limits, those of federal land ownership, the extent of administrative regions for various federal agencies, as well as the jurisdictional offshore limits of U.S. sovereignty. Boundaries associated solely with natural resources and/or cultural entities are excluded from this theme and are included in the appropriate subject themes."For other NGDA Content: Esri Federal Datasets
A global self-hosted Market Research dataset containing all administrative divisions, cities, addresses, and zip codes for 247 countries. All geospatial data is updated weekly to maintain the highest data quality, including challenging countries such as China, Brazil, Russia, and the United Kingdom.
Use cases for the Global Zip Code Database (Market Research data)
Address capture and validation
Map and visualization
Reporting and Business Intelligence (BI)
Master Data Mangement
Logistics and Supply Chain Management
Sales and Marketing
Data export methodology
Our map data packages are offered in variable formats, including .csv. All geographic data are optimized for seamless integration with popular systems like Esri ArcGIS, Snowflake, QGIS, and more.
Product Features
Fully and accurately geocoded
Administrative areas with a level range of 0-4
Multi-language support including address names in local and foreign languages
Comprehensive city definitions across countries
For additional insights, you can combine the map data with:
UNLOCODE and IATA codes
Time zones and Daylight Saving Times
Why do companies choose our Market Research databases
Enterprise-grade service
Reduce integration time and cost by 30%
Weekly updates for the highest quality
Note: Custom geographic data packages are available. Please submit a request via the above contact button for more details.
Austin's Communications & Technology Management Department is pleased to provide this zip code dataset for general use, designed to support a variety of research and analysis needs. Please note that while we facilitate access to this data, the dataset is owned and produced by the United States Postal Service (USPS). Users are encouraged to acknowledge USPS as the source when utilizing this dataset in their work.
U.S. ZIP Code Areas (Five-Digit) represents five-digit ZIP Code areas used by the U.S. Postal Service to deliver mail more effectively. The first digit of a five-digit ZIP Code divides the United States into 10 large groups of states numbered from 0 in the Northeast to 9 in the far West. Within these areas, each state is divided into an average of 10 smaller geographical areas, identified by the second and third digits. These digits, in conjunction with the first digit, represent a sectional center facility or a mail processing facility area. The fourth and fifth digits identify a post office, station, branch or local delivery area.
This product is for informational purposes and may not have been prepared for or be suitable for legal, engineering, or surveying purposes. It does not represent an on-the-ground survey and represents only the approximate relative location of property boundaries. This product has been produced by the City of Austin for the sole purpose of geographic reference. No warranty is made by the City of Austin regarding specific accuracy or completeness.
This is a MD iMAP hosted service. Find more information at http://imap.maryland.gov. In 1993 - the Maryland Department of Planning and the Maryland State Highway Administration entered into a Data Base Usage Agreement with Bell Atlantic and Data Chromatics - Inc. to develop an enhanced street address map for Maryland. ZIP Code boundary area files were one of the products derived from this partnership. The resulting boundary area files were intended to improve the cartographic quality and accuracy of the ZIP code boundary area files derived from the U.S. Census Bureau's post 1990 Census TIGER\Line Files (based on the Census Bureau's ZIP code tabulation areas - ZCTAs). Subsequent iterative improvements to the ZIP Code boundary area files have been made using premise address information associated with mapped parcel records as provided in the Maryland Department of Planning's MdProperty View GIS tax map and parcel record DVD product. The resulting files are meant to serve as a good approximation"" of ZIP codes as polygons (which in reality they are not) but are not official ZIP Code maps and are not meant to be a substitute for any products offered by the U.S. Postal Service - the official source for ZIP code information. While there are no restrictions on their use we do recommend that they are best used with MdProperty View and that MDP makes no guarantee or warranty regarding the files. Last Updated: 2012Feature Service Link:https://mdgeodata.md.gov/imap/rest/services/Boundaries/MD_PoliticalBoundaries/FeatureServer ADDITIONAL LICENSE TERMS: The Spatial Data and the information therein (collectively the ""Data"") is provided "as is" without warranty of any kind either expressed implied or statutory. The user assumes the entire risk as to quality and performance of the Data. No guarantee of accuracy is granted nor is any responsibility for reliance thereon assumed. In no event shall the State of Maryland be liable for direct indirect incidental consequential or special damages of any kind. The State of Maryland does not accept liability for any damages or misrepresentation caused by inaccuracies in the Data or as a result to changes to the Data nor is there responsibility assumed to maintain the Data in any manner or form. The Data can be freely distributed as long as the metadata entry is not modified or deleted. Any data derived from the Data must acknowledge the State of Maryland in the metadata.
MIT Licensehttps://opensource.org/licenses/MIT
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ZCTAs are approximate area representations of U.S. Postal Service (USPS) 5-digit ZIP Code service areas that the Census Bureau creates using census blocks to present statistical data from censuses and surveys. The Census Bureau defines ZCTAs by allocating each block that contains addresses to a single ZIP Code tabulation area, usually to the ZCTA that reflects the most frequently occurring ZIP Code for the addresses within that block. Blocks that do not contain addresses but that are completely surrounded by a single ZIP Code tabulation area (enclaves) are assigned to the surrounding ZCTA; those surrounded by multiple ZCTAs will be added to a single ZCTA based on the longest shared border. The Census Bureau identifies ZCTAs using a 5-character code that represents the most frequently occurring USPS ZIP Code within that ZCTA. This code may contain leading zeros. Users should not use ZCTAs to identify the official USPS ZIP Code for mail delivery. The USPS makes periodic changes to ZIP Codes to support more efficient mail delivery. ZIP Codes that cover primarily nonresidential or post office box addresses may not have a corresponding ZCTA because the delineation process uses primarily residential addresses, resulting in a bias towards ZIP Codes used for city-style mail delivery.
This dataset contains all zip codes in Montgomery County. Zip codes are the postal delivery areas defined by USPS. Zip codes with mailboxes only are not included. https://gis3.montgomerycountymd.gov/arcgis/rest/services/general/zipcode/MapServer/0
The 2020 cartographic boundary KMLs are simplified representations of selected geographic areas from the U.S. Census Bureau's Master Address File / Topologically Integrated Geographic Encoding and Referencing (MAF/TIGER) Database (MTDB). These boundary files are specifically designed for small-scale thematic mapping. When possible, generalization is performed with the intent to maintain the hierarchical relationships among geographies and to maintain the alignment of geographies within a file set for a given year. Geographic areas may not align with the same areas from another year. Some geographies are available as nation-based files while others are available only as state-based files. ZIP Code Tabulation Areas (ZCTAs) are approximate area representations of U.S. Postal Service (USPS) ZIP Code service areas that the Census Bureau creates to present statistical data for each decennial census. The Census Bureau delineates ZCTA boundaries for the United States, Puerto Rico, American Samoa, Guam, the Commonwealth of the Northern Mariana Islands, and the U.S. Virgin Islands once each decade following the decennial census. Data users should not use ZCTAs to identify the official USPS ZIP Code for mail delivery. The USPS makes periodic changes to ZIP Codes to support more efficient mail delivery. The Census Bureau uses tabulation blocks as the basis for defining each ZCTA. Tabulation blocks are assigned to a ZCTA based on the most frequently occurring ZIP Code for the addresses contained within that block. The most frequently occurring ZIP Code also becomes the five-digit numeric code of the ZCTA. These codes may contain leading zeros. Blocks that do not contain addresses but are surrounded by a single ZCTA (enclaves) are assigned to the surrounding ZCTA. Because the Census Bureau only uses the most frequently occurring ZIP Code to assign blocks, a ZCTA may not exist for every USPS ZIP Code. Some ZIP Codes may not have a matching ZCTA because too few addresses were associated with the specific ZIP Code or the ZIP Code was not the most frequently occurring ZIP Code within any of the blocks where it exists. The generalized ZCTA boundaries in this file are based on those delineated following the 2020 Census.
The TIGER/Line shapefiles and related database files (.dbf) are an extract of selected geographic and cartographic information from the U.S. Census Bureau's Master Address File / Topologically Integrated Geographic Encoding and Referencing (MAF/TIGER) Database (MTDB). The MTDB represents a seamless national file with no overlaps or gaps between parts, however, each TIGER/Line shapefile is designed to stand alone as an independent data set, or they can be combined to cover the entire nation. ZIP Code Tabulation Areas (ZCTAs) are approximate area representations of U.S. Postal Service (USPS) ZIP Code service areas that the Census Bureau creates to present statistical data for each decennial census. The Census Bureau delineates ZCTA boundaries for the United States, Puerto Rico, American Samoa, Guam, the Commonwealth of the Northern Mariana Islands, and the U.S. Virgin Islands once each decade following the decennial census. Data users should not use ZCTAs to identify the official USPS ZIP Code for mail delivery. The USPS makes periodic changes to ZIP Codes to support more efficient mail delivery. The Census Bureau uses tabulation blocks as the basis for defining each ZCTA. Tabulation blocks are assigned to a ZCTA based on the most frequently occurring ZIP Code for the addresses contained within that block. The most frequently occurring ZIP Code also becomes the five-digit numeric code of the ZCTA. These codes may contain leading zeros. Blocks that do not contain addresses but are surrounded by a single ZCTA (enclaves) are assigned to the surrounding ZCTA. Because the Census Bureau only uses the most frequently occurring ZIP Code to assign blocks, a ZCTA may not exist for every USPS ZIP Code. Some ZIP Codes may not have a matching ZCTA because too few addresses were associated with the specific ZIP Code or the ZIP Code was not the most frequently occurring ZIP Code within any of the blocks where it exists. The ZCTA boundaries in this release are those delineated following the 2020 Census.
https://www.nconemap.gov/pages/termshttps://www.nconemap.gov/pages/terms
This data represents five-digit ZIP Code areas used by the U.S. Postal Service. This is an ArcGIS Online item directly from Esri. For more information see https://www.arcgis.com/home/item.html?id=8d2012a2016e484dafaac0451f9aea24.
Austin's Communications & Technology Management Department is pleased to provide this zip code dataset for general use, designed to support a variety of research and analysis needs. Please note that while we facilitate access to this data, the dataset is owned and produced by the United States Postal Service (USPS). Users are encouraged to acknowledge USPS as the source when utilizing this dataset in their work. U.S. ZIP Code Areas (Five-Digit) represents five-digit ZIP Code areas used by the U.S. Postal Service to deliver mail more effectively. The first digit of a five-digit ZIP Code divides the United States into 10 large groups of states numbered from 0 in the Northeast to 9 in the far West. Within these areas, each state is divided into an average of 10 smaller geographical areas, identified by the second and third digits. These digits, in conjunction with the first digit, represent a sectional center facility or a mail processing facility area. The fourth and fifth digits identify a post office, station, branch or local delivery area. This product is for informational purposes and may not have been prepared for or be suitable for legal, engineering, or surveying purposes. It does not represent an on-the-ground survey and represents only the approximate relative location of property boundaries. This product has been produced by the City of Austin for the sole purpose of geographic reference. No warranty is made by the City of Austin regarding specific accuracy or completeness.
Attribution-ShareAlike 4.0 (CC BY-SA 4.0)https://creativecommons.org/licenses/by-sa/4.0/
License information was derived automatically
U.S. ZIP Code Areas (Five-Digit) represents five-digit ZIP Code areas used by the U.S. Postal Service to deliver mail more effectively. The first digit of a five-digit ZIP Code divides the United States into 10 large groups of states numbered from 0 in the Northeast to 9 in the far West. Within these areas, each state is divided into an average of 10 smaller geographical areas, identified by the second and third digits. These digits, in conjunction with the first digit, represent a sectional center facility or a mail processing facility area. The fourth and fifth digits identify a post office, station, branch or local delivery area.
MIT Licensehttps://opensource.org/licenses/MIT
License information was derived automatically
This layer shows the ZIP Code level boundaries of Montgomery County in 2020. This polygon layer includes only ZIP Codes with a delivery area. It does not include Post Office locations or ZIP Codes for large volume single customers.For more information, contact: GIS Manager Information Technology & Innovation (ITI) Montgomery County Planning Department, MNCPPC T: 301-650-5620
Attribution 4.0 (CC BY 4.0)https://creativecommons.org/licenses/by/4.0/
License information was derived automatically
Map of Zip Code boundaries within the City of Syracuse is from Syracuse Onondaga County Planning Agency (SOCPA) and was last revised in 2017. Due to an increase in population or to the improve postal operations, the US Postal Service® will occasionally add a new ZIP Code or change ZIP Code boundaries. This map of Zipcode boundaries within the City of Syracuse boundaries is accurate as of 2/2022.The five digits of a ZIP code (e.g.,12345) may be grouped as follows: [123] [45][123] : Sectional Center or Large City[45] : Post Office facility or Delivery AreaMore information regarding this can be found at: https://faq.usps.com/s/article/ZIP-Code-The-Basics
GeoJunxion‘s ZIP+4 is a complete dataset based on US postal data consisting of plus 35 millions of polygons. The dataset is NOT JUST a table of spot data, which can be downloaded as csv or other text file as it happens with other suppliers. The data can be delivered as shapefile through a single RAW data delivery or through an API.
The January 2021 USPS data source has significantly changed since the previous delivery. Some States have sizably lower ZIP+4 totals across all counties when compared with previous deliveries due to USPS parcelpoint cleanup, while other States have a significant increase in ZIP+4 totals across all counties due to cleanup and other rezoning. California and North Carolina in particular have several new ZIP5s, contributing to the increase in distinct ZIPs and ZIP+4s.
GeoJunxion‘s ZIP+4 data can be used as an additional layer on an existing map to run customer or other analysis, e.g. who is my customer who not, what is the density of my customer base in a certain ZIP+4 etc.
Information can be put into visual context, due to the polygons, which is good for complex overviews or management decisions. CRM data can be enriched with the ZIP+4 to have more detailed customer information.
Key specifications:
Topologized ZIP polygons
GeoJunxion ZIP+4 polygons follow USPS postal codes
ZIP+4 code polygons:
ZIP5 attributes
State codes.
Overlapping ZIP+4
boundaries for multiple ZIP+4 addresses on one area
Updated USPS source (January 2021)
Distinct ZIP5 codes: 34 731
Distinct ZIP+4 codes: 35 146 957
The ZIP + 4 polygons are delivered in Esri shapefile format. This format allows the storage of geometry and attribute information for each of the features.
The four components for the shapefile data are:
.shp – This file stores the geometry of the feature
.shx –This file stores an index that stores the feature geometry
.dbf –This file stores attribute information relating to individual features
.prj –This file stores projection information associated with features
Current release version 2021. Earlier versions from previous years available on request.
Our India zip code Database offers comprehensive postal code data for spatial analysis, including postal and administrative areas. This dataset contains accurate and up-to-date information on all administrative divisions, cities, and zip codes, making it an invaluable resource for various applications such as address capture and validation, map and visualization, reporting and business intelligence (BI), master data management, logistics and supply chain management, and sales and marketing. Our location data packages are available in various formats, including CSV, optimized for seamless integration with popular systems like Esri ArcGIS, Snowflake, QGIS, and more. Product features include fully and accurately geocoded data, multi-language support with address names in local and foreign languages, comprehensive city definitions, and the option to combine map data with UNLOCODE and IATA codes, time zones, and daylight saving times. Companies choose our location databases for their enterprise-grade service, reduction in integration time and cost by 30%, and weekly updates to ensure the highest quality.
MassGIS had received quarterly updates of these data as part of its license for the HERE (Navteq) core map release (streets and related data); however, that license has expired. These ZIP Code boundaries are aligned to the street centerlines of the Q2 2018 HERE product (with a release date of April 1, 2018) and use a then-recent USPS source file.In March 2024, MassGIS modified the boundaries for all ZIP Code areas in Boston based on the U.S. Postal Service's ZIP Code Look Up by Address website. MassGIS also added polygons for ZIP Codes 02199 and 02203.Five-digit ZIP Codes were developed by the USPS and first introduced in 1963 for efficient mail delivery (the term ZIP stands for Zone Improvement Plan) but are difficult to map with complete certainty. In most cases, addresses in close proximity to each other are grouped in the same ZIP Code, which gives the appearance that ZIP Codes are defined by a clear geographic boundary. However, even when ZIP Codes appear to be geographically grouped, a clear ZIP Code boundary cannot always be drawn because ZIP Codes are only assigned to a point of delivery and not the spaces between delivery points. In areas without a regular postal route or no mail delivery, ZIP Codes may not be defined or have unclear boundaries.The USPS does not maintain an official ZIP Code map. The Census Bureau and many other commercial services will interpolate the data to create polygons to represent the approximate area covered by a ZIP code, but none of these maps are official or entirely accurate. Please see this good discussion of the issues of mapping ZIP Codes.See full metadata.Map service also available.