Developed land: A combination of land cover/use categories, including urban and built-up areas and rural transportation land. Urban and built-up areas consist of residential, industrial, commercial, and institutional land; construction sites; public administrative sites; railroad yards; cemeteries; airports; golf courses; sanitary landfills; sewage treatment plants; water control structures and spillways; other land used for such purposes; small parks (less than 10 acres) within urban and built-up areas; and highways, railroads, and other transportation facilities if they are surrounded by urban areas. Included are tracts of less than 10 acres that do not meet the above definition but are completely surrounded by urban and built-up land. Two size categories are recognized in the NRI: (a) small built-up areas of 0.25 acre to 10 acres and (b) large urban and built-up areas of at least 10 acres. In 1997, both size categories accounted for 78 percent of total developed land.

Rural transportation land consists of all highways, roads, railroads, and associated rights-of-way outside urban and built-up areas, including private roads to farmsteads or ranch headquarters, logging roads, and other private roads, except field lanes. In 1997, this category accounted for the remaining 22 percent of total developed land.

Sources: NRCS 2002; NRCS 2003.