Westamerica Bancorp is based in San Rafael, California. Westamerica Bancorporation runs a regional community bank and has approximately $7.5 billion in assets. The banks' net revenue is generated by net interest income. Deposit service charges make up the noninterest income sources. The bank focuses mostly on commercial clients, such as smaller businesses. Its footprint encompasses central and northern California, extending north of San Francisco to Mendocino and Lake counties, south to Kern County in central California, and all the way east to Nevada County.