The mining claim density data of federal lands in California are combined with the digital California Public Land Survey (PLS) to create a digital map of the density of mine claims in Open-File Report 99-409. The mining claim density data of federal lands in California was one of 13 western states released in Open-File Report 99-325. The database for California was converted to an Arc/Info file and connected with the PLS by an Arc/Info relate. As stated in OF 99-325, "These mining claim density databases were created from data obtained in March 1997, from the Mining Claim Recordation System (MCRS) of the Bureau of Land Management. These databases provide mining claim density information in a tabular form. They quantify the status of mining claim activity for 1996 and include information on mining claim activity since 1976. The databases contain information identifying 1) the general location of mining claims within the Public Land Survey System (PLS), 2) the number and type of claims (lode, placer, mill site, tunnel site), and 3) the status of the claims (open is held, closed is no longer held by a claimant)". Combining the database with a digital PLS coverage of California enables a User to spatially display the mine claim data as a digital map and compare it with other spatial themes.