Tehama County Tehama County is a county located in the northern part of the U.S. state of California. As of the 2010 census, the population was 63,463. The county seat and largest city is Red Bluff. 645 Acres Almond & Walnut Orchard Orland, Ca 157.79 Acres Range Land – Red Bluff, CA Walnut Orchard, Red Bluff, CA Pistachios, Walnuts, and Prunes