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Start Over Year 1981 Subject Counties Theme Boundaries
1980, 1981, 1982, 1983, 1984, 1985, 1986, 1987, 1988, 1989, and 1990. Geological Survey (U.S.). This polygon shapefile portrays the 1990 state and county boundaries of the United States, Puerto Rico, and the U.S. Virgin Islands. The map layer ... Geological Survey (U.S.).