User:JPxG/List of quadripoints in the United States

Posts online. Overpass query: node["boundary"="administrative"]["admin_level"="6"]({bbox}); way["boundary"="administrative"]["admin_level"="6"]({bbox}); relation["boundary"="administrative"]["admin_level"="6"]({bbox}); california: 1) sonoma, solano, contra costa and marin (in san pablo bay) 2) alameda, san joaquin, stanislaus and santa clara (at mt. boardman) 3) stanislaus, tuolumne, mariposa, merced (??)