McCourt School of Public Policy
Massive Data Institute

Census Geographies Project

Description of Project

This site is a work in progress

These resources are intended to assist decision makers and stakeholders in evaluating design choices for the nation’s major sources of small-area data produced for the public good by the U.S. Census Bureau—the decennial census, the American Community Survey (ACS), and the population estimates program. It may also assist people interested in the evolution of different governmental structures (political geography) in the United States, the invention of “statistical” geography to serve data user needs, and the bedrock importance of census, ACS, and population estimates small-area data for both political and statistical geography. Such data are essential for a wide range of consequential uses—redistricting of seats in legislatures and councils, allocation of state and federal funds, and planning, implementation, and evaluation of programs for schools, health care, emergency and disaster assistance, and many other services. 

Political geography includes general-purpose functioning governments—states, counties, cities, towns, and other units. Political geography varies substantially within and across states in population size and land area. Statistical geography includes units defined according to specified criteria by the Census Bureau or another federal agency—metropolitan statistical areas, census tracts, blocks, and other units. Such units are intended to provide data for socioeconomically meaningful areas in a standard way across the nation.