In 1850 Santa Ana County was bounded on the north by Rio Arriba County, east by Santa Fe County, west by the California line, and south by a line near Bernalillo County.  In 1875-76 Santa Ana County was added to Bernalillo County and the name disappeared. Present area included in the 1850 census is: part of the state of Arizona, and portions of McKinley, Sandoval, Bernalillo, and Valencia Counties, N.M.