Throughout the second half of the twentieth century, the gold standard for mapping in the United States was the 7.5' USGS topographic map. Created at a scale of 1:24,000 (2 5/8th" to the mile), these maps show landscape details as small as individual farm fields, seasonal streams, and the shape of large buildings.
An incredibly expensive undertaking, towards the end of the paper mapping program the USGS would produce a new quadrangle map only when another agency contracted it to do so. Most topographic maps produced after the year 2000 were of National Forest lands.
All current, and most former, quadrangle maps are available for download from the USGS Map Locator and Downloader as geoPDFs. Historical topographic maps are available from the USGS Historical Topographic Map Explorer.
Detailed information about print copies of USGS topos in the collection are on the main map collection page. Generally speaking, the Library holds all California USGS topographic maps. All editions and all scales.