UPDATE 4 a.m. Friday: All lanes are now open.
Deputies are currently working an accident near the U.S. 231 N. near the William H. Natcher bridge.
A crash involving a tractor-trailer has blocked the northbound lanes of U.S. 231 The southbound lanes are open.
Motorists are encouraged to seek alternate routes until further notice. The duration of the closure is currently estimated at four hours.