Arkansas Highway 251 is a north–south state highway in Randolph County, Arkansas. The route runs 15.28 miles (24.59 km) from Arkansas Highway 115 near Pocahontas north to the Missouri state line. The route does not cross or concur with any other state highways.

AR 251 begins at Highway 115 north of Pocahontas. The route heads north with AR 328 and AR 231 shooting from the route before terminating at Missouri supplemental route P.

The entire route is in Randolph County.