Biohazard Cleanup Near Downtown Seneca Seneca, OR

Seneca is a city in Grant County, Oregon, in the Blue Mountains about 23 miles south of Canyon City on U.S. Route 395, on the edge of the Malheur National Forest.

Seneca sits at the confluence of Bear Creek and the Silvies River in Bear Valley, at the northern edge of the Great Basin, at an elevation of 4,675 feet.

Seneca's post office was established in 1895 and named by postmaster Minnie Southworth for her brother-in-law, prominent Portland judge Seneca Smith.

Seneca only began growing in 1929, when it became the northern terminus of the Oregon and Northwestern Railroad, owned by the Edward Hines Lumber Company, which shipped Ponderosa pine logs south to the Hines sawmill in Hines.

The Hines company built a planing mill and railroad shops in Seneca, making it essentially a company town, and Seneca was incorporated as a city in 1970 as lumber company control began to wane.

Logging in the Seneca area declined in the 1970s, and the Hines company ceased operations of its lumber mills and railroad in 1984.

Seneca experiences the coolest weather in Grant County and holds the distinction of the coldest official temperature ever recorded in Oregon: minus 54 degrees Fahrenheit in 1933.

The 2020 census recorded 165 residents in Seneca, living in 79 households, with a median age of 54.8 years.

Seneca covers 0.80 square miles of land, and its main industries are cattle ranching and timber production.

Seneca is served by the Grant School District, and Seneca School, a kindergarten through fifth grade school built in the 1930s for Hines Lumber Company employees, had 58 students as of 2011.