[6] It is located approximately 15 mi (24 km) southeast of Bodega Bay, on State Route 1.

The town is named after the Marshalls, four brothers who set up a dairying industry there in the 1850s.

Starting in the 1870s, Marshall was a stop on the North Pacific Coast Railroad connecting Cazadero to the Sausalito ferry.

There is still some dairying in the area with Straus Family Creamery based there, but nowadays the town's major commerce is in oysters and clams, for which it is a center.

It also acts as a center for tourists visiting Tomales Bay and the neighboring Point Reyes Peninsula.