Brentwood (Images of America: California) Paperback by Carol A. Jensen (Author), East Contra Costa Historical Society (Author) The beautiful Brentwood area of Contra Costa County is the oldest continuously populated community in California inland from the great coastal centers. Californios eschewed this challenging portion of the Central Valley, so pioneering physician John Marsh established a permanent settlement here in 1837 at his Rancho Los Meganos. Soon, the burgeoning viniculture, wheat, orchard, and cattle operations attracted many Gold Rush miners back to their original agricultural callings, now in the California Delta. The 1860s arrival of British agribusiness concern Balfour Guthrie Investment Company soon established the largest grain-export and fruit-packing venture in the West. Brentwood Township, established in 1878 and named for Marsh’s ancestral home in England, includes some of the state’s most bountiful land. The region fostered the greatest wheat production west of the Mississippi River during the 19th century.