Census block

Definition
The U.S. Census Bureau defines a census block as a statistical area bounded by visible features, such as streets, roads, streams, and railroad tracks, and by nonvisible boundaries, such as selected property lines and city, township, school districts, and county boundaries. A block is the smallest geographic unit for which the Census Bureau tabulates decennial census data. Many blocks correspond to individual city blocks bounded by streets, but blocks &mdash; especially in rural areas &mddash; may include many square miles and may have some boundaries that are not streets.