Seneca post office was established in 1895 and named by postmaster Minnie Southworth for her brother-in-law, prominent Portland judge Seneca Smith [REF].
While early homesteaders moved into the valley in the late 1800s, Seneca only began growing in the 1929 when it became the northern terminus of the now-vacated Oregon and Northwestern Railroad, owned by the Edward Hines Lumber Company, which extended south to Burns [REF].