This dataset includes census blocks as delineated by the U.S. Census Bureau and made available through their TIGER/Line files. These delineations were prepared for tabulation of the 2010 decennial census data. Blocks are statistical areas bounded by visible natural landforms and man-made structures, such as streets, roads, streams, and railroad tracks, and by nonvisible limits, such as selected property lines and city, township, school district, and county limits and short line-of-sight extensions of streets and roads. Generally, census blocks are small in area; for example, a block in a city bounded on all sides by streets. Census blocks are numbered uniquely with a four-digit census block number from 0000 to 9999 within census tract, which nest within state and county. The first digit of the census block number identifies the block group. Block numbers beginning with a zero (in Block Group 0) are only associated with water-only areas. For more information about census geographies, see http://www.census.gov/geo/reference/ . This file is for reference use only. NCTCOG and its members are not responsible for errors or inaccuracies in the file.