California Historic Topographic Map Collection (California State University , Chico)
This site provides access to historic topographic maps from the late 1800's to the early 1900's. The scales for the maps available range from 1:24,000 - 1:125,000.
CASIL - California Digital Raster Graphics
The Digital Raster Graphic (DRG) is a raster image of a scanned USGS topographic map including the collar information. The source maps for DRGs were georeferenced to the UTM grid, but DRG images for California are available in Albers equal area projection (see the projection information). The maps are available for download in TIF format.
Los Angeles County Historical Topographic Maps
This collection of historical topographic maps was first created during the 1920s and 1930s. The maps are at a 1:24,000 scale.
The TerraServer-USA Web site is one of the world's largest online databases, providing free public access to a vast data store of maps and aerial photographs of the United States. You can easily navigate the enormous amount of information in TerraServer by selecting a location on a map or entering a place name.
TopoZone is one the Web's best interactive topographic map for the entire United States.