U.S. Census Bureau, data file from Geography Division based on the TIGER/Geographic Identification Code Scheme (TIGER/GICS) computer file. Land area updated every 10 years. http://www.census.gov/geo/www/tiger/index.html or http://factfinder2.census.gov.

Land area is the size, in square units (metric and nonmetric) of all areas designated as land in the Census Bureau's national geographic (TIGER®) database.