River Pines is a census-designated place in Amador County, California. It is located 3 miles north-northeast of Fiddletown, at an elevation of 1985 feet. A post office opened at River Pines in 1948; it has the zip code of 95675. River Pines has a population of 379.In the 1920s, the growing middle class looked for weekend or summer vacation property to buy a cabin amid the pines. Developers Roy and Helen Brooke found suitable land along the south fork of the Cosumnes in the Bridgeport district, and developed River Pines Resort to sell cabin sites. By damming the river, the resort developed water activities and sports. With the resort thriving for a time, the Brookes subdivided more land for lots. In time, the resort became just another rural, remote community with a post office and store and lots of privacy.