Bank of Marin has opened a new full-service branch in downtown Santa Rosa.

The branch, located at 50 Santa Rosa Ave., is its fourth location in Sonoma County. The Novato-based bank has three branches in Petaluma and 13 other offices across Marin, Napa and San Francisco counties. It plans to open a location in the town of Sonoma later this year.

Dave Brown is manager of the Santa Rosa branch, which since October was operating solely as a loan office.

The bank has about $1.3 billion in assets.