County boundaries of selected United States territories/states, 1790-1980

This cartographic data base was created at the University of Wisconsin-Madison Cartographic Laboratory in conjunction with the Newberry Library and the National Endowment for the Humanities. The collection makes it possible to plot any or all of the territorial/state and county boundaries in the region covered by the states of North and South Dakota, Minnesota, Iowa, Missouri, Wisconsin, Illinois, Michigan, Indiana, Ohio, Pennsylvania, New Jersey, Maryland, and Delaware. The data collection also contains the county names, the names and locations of the corresponding capitals and county seats, and the shoreline along the Great Lakes and the Atlantic Ocean. All changes in lines, locations, and names are dated to the day according to their legally effective dates. The data collection consists of forty files. All of the cartesian coordinates (in digitizer units) required to define the historical county boundaries for those fourteen states are contained in one file. A second file contains the ''control'' needed to convert digitizer units into latitude and longitude. These two files have a logical record length of 132 characters. The remaining thirty-eight files are data files containing