In 2023, Washington, D.C. had the highest population density in the United States, with 11,130.69 people per square mile. As a whole, there were about 94.83 residents per square mile in the U.S., and Alaska was the state with the lowest population density, with 1.29 residents per square mile. The problem of population density Simply put, population density is the population of a country divided by the area of the country. While this can be an interesting measure of how many people live in a country and how large the country is, it does not account for the degree of urbanization, or the share of people who live in urban centers. For example, Russia is the largest country in the world and has a comparatively low population, so its population density is very low. However, much of the country is uninhabited, so cities in Russia are much more densely populated than the rest of the country. Urbanization in the United States While the United States is not very densely populated compared to other countries, its population density has increased significantly over the past few decades. The degree of urbanization has also increased, and well over half of the population lives in urban centers.

The 2015 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. The records in this file allow users to map the parts of Urban Areas that overlap a particular county. After each decennial census, the Census Bureau delineates urban areas that represent densely developed territory, encompassing residential, commercial, and other nonresidential urban land uses. In general, this territory consists of areas of high population density and urban land use resulting in a representation of the "urban footprint." There are two types of urban areas: urbanized areas (UAs) that contain 50,000 or more people and urban clusters (UCs) that contain at least 2,500 people, but fewer than 50,000 people (except in the U.S. Virgin Islands and Guam which each contain urban clusters with populations greater than 50,000). Each urban area is identified by a 5-character numeric census code that may contain leading zeroes. The primary legal divisions of most states are termed counties. In Louisiana, these divisions are known as parishes. In Alaska, which has no counties, the equivalent entities are the organized boroughs, city and boroughs, municipalities, and for the unorganized area, census areas. The latter are delineated cooperatively for statistical purposes by the State of Alaska and the Census Bureau. In four states (Maryland, Missouri, Nevada, and Virginia), there are one or more incorporated places that are independent of any county organization and thus constitute primary divisions of their states. These incorporated places are known as independent cities and are treated as equivalent entities for purposes of data presentation. The District of Columbia and Guam have no primary divisions, and each area is considered an equivalent entity for purposes of data presentation. The Census Bureau treats the following entities as equivalents of counties for purposes of data presentation: Municipios in Puerto Rico, Districts and Islands in American Samoa, Municipalities in the Commonwealth of the Northern Mariana Islands, and Islands in the U.S. Virgin Islands. The entire area of the United States, Puerto Rico, and the Island Areas is covered by counties or equivalent entities. The boundaries for counties and equivalent entities are as of January 1, 2010.

This dataset contains the boundaries of the Planning Areas of the NJ State Development and Redevelopment Plan (NJSDRP). The State Plan's Statewide Policies are applied to the natural and built resources of the state through the designation of five Planning Areas. These Planning Areas reflect distinct geographic and economic units within the state and serve as an organizing framework for application of the Statewide Policies of the State Plan. Planning Areas are areas of land, not less than one square mile, that share certain conditions, such as population density, infrastructure systems, level of development, or environmental sensitivity. Planning Areas do not necessarily coincide with municipal or county boundaries, but define geographic areas that are suitable for common application of public policy. The State Plan anticipates continued growth throughout New Jersey in all Planning Areas. The character, location and magnitude of this growth vary among Planning Areas according to the specific character of the area. Each Planning Area has Policy Objectives that guide growth in the context of its unique qualities and conditions. The Policy Objectives also shape and define the application of the Statewide Policies in each Planning Area. Refer to the NJSDRP for further description of the geographic nature of Planning Areas.

The dataset was last updated in 2008. The purpose of the Building Footprints dataset is to provide accurate and detailed information about the physical footprint and characteristics of buildings within Somerset County. The dataset primarily supports urban planning and land management activities. Planners and architects can utilize the dataset to assess land use patterns, monitor urban growth, and evaluate the impact of proposed developments. It aids in analyzing population density, urban sprawl, and the distribution of infrastructure and services. The dataset also plays a crucial role in emergency management and public safety. During emergencies or natural disasters, building footprints GIS data helps responders understand the spatial layout of structures, plan evacuation routes, and assess potential risks. Additionally, the dataset contributes to environmental analysis and sustainability initiatives. By overlaying the data with other layers such as vegetation, energy consumption, or solar potential, urban planners can assess the environmental impact of buildings, optimize energy efficiency, and promote sustainable design practices.