- North America21 objects
- The Americas21 objects
- United States✖Remove constraint Collection place: United States21 objects
- California11 objects
- CA-Col-1 (Miller Mound), Colusa County, California10 objects
- Churchill County, Nevada10 objects
- Colusa County, California10 objects
- NV-Ch-35 (Humboldt Cave), Churchill County, Nevada10 objects
- Nevada10 objects
- North Central California10 objects
- Northern California10 objects
- CA-CCo-141, Palm Tract, Contra Costa County1 objects
- Contra Costa County, California1 objects
- Palm Tract, Contra Costa County, California1 objects
- San Francisco Bay Area, California1 objects
- Unincorporated eastern Contra Costa County, California1 objects