 In Brown County, US-36 becomes a super two, intersecting the concurrency of US-73 and US-159 in Hiawatha.The highway becomes full-access again before entering Doniphan County for its final trek through the state, passing through Troy and into Wathena, where it picks up freeway status though Elwood before crossing the Missouri River on the Pony Express Bridges and entering Missouri.Prior to 1926, the portion of future US-36 between Norton and the Missouri state line was known as the Rock Island Highway.