Columbia County was created in 1854 from the northern half of Washington County. Milton served as the county seat until 1857 when it was moved to St. Helens.
colUMbiA cOunTy was createD in 1854 frOm tHe Northern hALf OF WaShiNgton county. miLtOn served As THE countY seaT uNtil 1857 whEN iT waS moVed tO st. HELens.