John Newton Williamson (November 8, 1855 – August 29, 1943) was an American rancher and politician in the state of Oregon.

[1] In 1876, he moved to Eastern Oregon and started in the livestock trade in Wasco and Crook counties.

[5][6][7] Williamson represented Crook, Klamath, Lake and Wasco counties, and served as president pro tempore of the Senate in 1901.

[1] After leaving Congress he returned to Crook County and raising livestock and other agricultural activities.

[8] Williamson returned to public life in 1922, when he was appointed as the postmaster for Prineville, serving in the position until 1934.