The Public Land Survey System (PLSS) is the way land in the United States is subdivided, it forms the foundation of Cook County's cadastral system for identifying and locating land records. Tax parcels are identified using township and section notation, in a modified format. The PLSS serves as a way for users to navigate the parcel geodatabase. This PLSS feature data set is intended to correspond to tax pages on the Cook County Tax Maps. They should not be used for measurement or surveyor purposes. In addition, the parcel attributes PINA (area/township) and PINSA (subarea/section) do not necessarily correspond to the PLSS township and section polygon in which a given parcel resides. The PLSS data is modeled as a single composite network coverage that encompasses townships (area), sections (subarea), quarter sections, and half quarter section. Tax map pages, which typically correspond to half quarter sections (in an east-west split), are modeled as a region subclass in the LANDFABRIC layer. If an indigenous people's reserve was present on the tax map, it was digitized to create subpolygons of the half-quarter section, and those polygons were attributed with the name of the reserve. Within this PLSS data set, a half-quarter section is the smallest polygon unit, except in cases where an Indigenous People's Reserve line is present. The cadastral data for Cook County have previously not been digital nor automated. This project is the initial automation for this information. This database was designed to represent a continuous, non-overlapping spatial database accounting for all land area in Cook County.The PLSS is updated as needed.

Forest Preserve District of Cook County boundaries. To view or use these shapefiles, compression software and special GIS software, such as ESRI ArcGIS, is required.

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. Face refers to the areal (polygon) topological primitives that make up MTDB. A face is bounded by one or more edges; its boundary includes only the edges that separate it from other faces, not any interior edges contained within the area of the face. The Topological Faces Shapefile contains the attributes of each topological primitive face. Each face has a unique topological face identifier (TFID) value. Each face in the shapefile includes the key geographic area codes for all geographic areas for which the Census Bureau tabulates data for both the 2020 Census and the annual estimates and surveys. The geometries of each of these geographic areas can then be built by dissolving the face geometries on the appropriate key geographic area codes in the Topological Faces Shapefile.

Hydrographic data was collected for all of Cook County. Significant flowing and standing water features that were visible on the aerial photography were stereocompiled from 1998 aerial photography. The hydrographic midline data set represents, as a single line, the interpreted midline of flowing water features as seen on the aerial photography. The hydrographic midline data layer is used to show the location of the midline of natural drainage features, and is connected to polygonal (standing) hydrographic features such as lakes and ponds. The midline data layer also includes drainage features less than five feet in width, which were not included in the polygon hydrography data set. Midlines were added to water bodies such as double-line rivers to maintain the linear connectivity of the hydrographic network. Where the course of linear features (such as streams and rivers) in the hydrographic midline layer could not be compiled photogrammetrically due to being obscured by other features (such as vegetation or shadows), the obscured line segment was coded as "interpreted". In some cases, a flowing water feature may have run through an underground drain or culvert or its course otherwise obscured from view on the aerial photography. For such cases, in order to maintain linear connectivity of the features, its path was also interpreted and coded as such. Some hydrographic data was provided by the City of Chicago and incorporated into this data layer. These hydrographic data layers are modeled and stored as a network coverage containing polygons and/or lines. This midline data layer was created out of need by Cook County to develop a hydrographic layer in which water features are represented as single lines. The intended primary use of this data layer is for small-scale mapping and networking. The hydrographic midline layer was intersected with the street midline and railroad data layers to create nodes in the coverage model. It was also intersected with the bridge polygon data layer. Where hydrographic midline segments fall within a bridge polygon, they have been given a grade separation code of zero (0) to indicate the water level is technically "at grade". Hydrographic attributes include feature name, tax map name, and type. The primary source of the attribute information was the Cook County Highway Department database. Hydrographic names and alias IDs are linked to lookup tables based on the hydrographic name ID attribute.

Cook County GIS Department map of municipal boundaries in Cook Cook County, Illinois in PDF format. Includes major streets, waterbodies, rail, Cook County Forest Preserve, and municipal boundaries.

DuPage County, IL boundary.

Cook County GIS Dept map of Lemont Township in a pdf format. Includes streets and municipalities.

Cook County GIS Department map of Cook County Commissioner District 14 in PDF format. Includes major streets, waterbodies, rail, and Cook County Commissioner District boundaries.

Cook County Municipalities layer displays the boundaries of all municipalities within Cook County, IL.

© Cook County GIS Department This layer is a component of Boundary data layers for the Green Infrastructure Atlas.

© Calumet Stormwater Collaborative & South Suburban Mayors and Managers Association

Cook County GIS Dept map of Commissioner District 10

Cook County GIS Dept map of Cook County Facilities in PDF format. The map shows all public Cook County Facilities, municipalities, Cook County highway jurisdiction, Cook County Commissioner Districts, major streets, highways, and water bodies.

KML file of Forest Preserve District of Cook County boundaries. To view or use these files, special GIS software such as Google Earth is required

This layer is a component of GIV Planning Data Layers.

© Calumet Stormwater Collaborative & South Suburban Mayors and Managers Association

Created for all users to view and understand jurisdictional boundaries within Cook County. GIS department maintains Municipality feature. Municipal boundary is aligned to the far side of the right of way in accordance with Illinois state statute. Data is updated periodically throughout the year.

Cook County GIS Dept map of Barrington Township in a pdf format. Includes streets and municipalities.

Cook County GIS Dept map of Commissioner District 13

Cook County GIS Dept map of Commissioner District 8

Cook County GIS Dept map of Commissioner District 3.

Cook County GIS Dept map of Commissioner District 11

Cook County GIS Dept map of Commissioner District 15