Seneca is situated on the Silvies River, Seneca is in Bear Valley at the northern edge of the Great Basin. While early homesteaders moved into the valley in the late 1800’s, Seneca began growing in the 1920’s as a company town for the Edward Hines Lumber Company, boasting a sawmill and the northern terminus of a (now-vacated) railroad track which extended south to Burns, Oregon.

Seneca experiences the coolest weather in Grant County, Oregon and has the distinction of the coldest official temperature recorded in the Oregon: 54 degrees below zero. The main industries in Seneca are ranching and timber production.