U.S. Federal Route 51 is a controlled access highway from the Dyer/Obion County Line to near Troy. From near Troy to the northside of Union City, this is a four-lane highway. North of Union City to near the Kentucky State Line it is a controlled access highway. U.S. Rt. 51 passes through the following town in Obion County. Union City U.S. Rt. 51 is multi-plexed in Obion County. Tennessee State Route 3, through out Obion County. Tennessee State Route 22, at Union City. U.S. Rt. 45W, from near Union City to near South Fulton.