"Contra Costa" is Spanish for "opposite coast" (when viewed across the bay from San Francisco). Much of what was seen of Contra Costa from San Francisco in the Spanish colonial (1776-1821) and Mexican provincial (1821-1846) periods is now within the county of Alameda. While the cities of Richmond and Kensington remain with views of San Francisco bay, and the county seat, Martinez, lies on the Sacramento River, the bulk of the county is inland, over the hills seen from San Francisco and extends east to the San Juaquin river and south to the vicinity of interstate highway 580 in the Livermore valley.