After Mexico achieved independence, it continued to rule California. After the Mexican Cession and the Treaty of Guadalupe Hidalgo in 1848, the area became part of the United States. Tulare County was soon formed from parts of Mariposa County only 4 years later in 1852. There were two early attempts to split off a new Buena Vista County in 1855 and Coso County in 1864, but both failed. Parts of the county's territory were given to Fresno County in 1856, to Kern County and to Inyo County in 1866 and to Kings County in 1893.