You can map at the county, tract, or block group level . Although you can select up 25 variables, only the first variable will be mapped. If you don't know the county in which a city is located, use the Geographic Names Information System database to find the county name. This software displays EPA-regulated sites and demographic and economic data from the 1990 Census. This information can be overlayed on the network of U.S. streets, water features, and political and census boundaries.
LandViewIII page provides technical documentation, tutorials, FAQs, and other information.
National Digital Map Library Select a state or states and variables to create an online map derived from U.S.G.S. Digital Line Graph Data. Variables include federal lands by type, most populated places, highways, rivers, railroads, historic sites, battlefields, and county lines. Service of the University of Virginia. Many publications are available online in the Adobe Acrobat .pdf format. You can sometimes download the Acrobat reader from sites offering documents in this format.