Cool graphic showing Census documented changes in about 10 urban areas. via The Center for Urban Research and the CUNT Graduate Center.

"The National Historical Geographic Information System (NHGIS) provides, free of charge, aggregate census data and GIS-compatible boundary files for the United States between 1790 and 2011."

A need website of old maps which have been digitized... here more for fun, really

"INSIDE Idaho is the official geospatial data clearinghouse for the State of Idaho."

"This portal is designed to support our goal to build a comprehensive Enterprise Geographic Information System (GIS) that promotes location information sharing and the effective use of geospatial technology and science.

Maps and data on the GIS are representations of real-world conditions. With consideration for the intended use of the map, appropriate effort is made to ensure the accuracy of the data, but errors in mapping and errors in source documents do occur. As such the City of Pullman assumes no liability for errors, omissions or inaccuracies regardless of cause, or for any decision made, action taken, or not taken, as a result of reliance upon any maps. See our data accuracy and terms of use here"

"Visual selection of the latitude / longitude coordinates for geotagging "