State Route 116 (SR 116) is a state highway in the U.S. state of California in Sonoma County. The route runs from State Route 1 on the Pacific coast near Jenner to State Route 121 south of Sonoma.

This route is part of the California Freeway and Expressway System and is eligible for the State Scenic Highway System. However, it is only a scenic highway as designated by Caltrans from SR 1 to the Sebastopol city limit.

State Route 116 proceeds east along the north bank of the Russian River, from State Route 1 to Guerneville, passing through Duncans Mills, Monte Rio, and Guernewood Park. In this section, it is generally called River Road.

At Guerneville, the route turns south-east and passes through Forestville, Graton, and Sebastopol (where it intersects State Route 12) to join U.S. Route 101 in Cotati. In this section, it is generally called Guerneville Highway or Gravenstein Highway.

The route follows the U.S. 101 alignment south from Cotati to Petaluma, a stretch Caltrans calls the Cotati Grade.

From southern Petaluma, State Route 116 diverges from 101 and heads east again, crossing the Sonoma Mountains directly north of Tolay Lake and descending into the Sonoma Valley to its terminus at State Route 121. In this section, it goes by several names: Lakeville Highway, Stage Gulch Road, and Arnold Drive.

Except where prefixed with a letter, postmiles were measured on the road as it was in 1964, and do not necessarily reflect current mileage. The entire route is in Sonoma County.