The river was originally known among the Southern Pomo as Ashokawna (ʼaš:oʼkʰawna), “east water place” or “water to the east”, and as Bidapte, “big river”.
The earliest European name for the river, Slavyanka appears on a Russian-American Company chart dated 1817.
In 1827 it was called the San Ygnacio by the Spanish, and in 1843 Spanish land grant referred to it as Rio Grande.
The river takes its current name from the Russian Ivan Aleksandrovich Kuskov of the Russian-American Company who explored the river in the early 19th century, and established the Fort Ross colony 10 mi (16 km) northwest of its mouth. They called it the Slavyanka River (Славянка), meaning “Slav River”.
The Russians established three ranches near Fort Ross, one of which – the Kostromitinov Ranch – was along the Russian River near the mouth of Willow Creek. The redwoods that lined its banks drew loggers to the river in the late 19th century.
According to the USGS, variant names of the Russian River include Misallaako, Rio Ruso, Shabaikai, and Slavyanka.
According to Russian sources the first grape plantations were built by Russian settlers. I found only one source in English mentioning it.