Land use and land use changes between 1961 and 1970 were interpreted from Agricultural Stabilization and Conservation Service (ASCS) 1:20,000 scale photography for 53 rapid-growth counties. In these counties, which experienced about 20 percent of the total U.S. population increase between 1960 and 1970, urban land accounted for 16 percent of the area in 1970, up from 13 percent in 1961. Of land developed for urban use in the 53-county aggregate between 1961 and 1970, 35 percent had been cropland, 28 percent forest, and 33 percent open idle. Regionally, the amount of urban development on various types of rural land differed considerably. While total land in rural uses remained relatively the same over the period, shifts among rural uses were an important aspect of land use change. The average amount of land urbanized per person increase in population for the 53-county total was .173 acres. While this per capita ratio varied regionally, in all regions new urban development occurred at a higher density than had previous urban development.