SR 149 begins at an interchange with SR 7 in Bellaire, just west of the Ohio River. The route heads west on 26th Street through Bellaire paralleling the McMahon Creek. Shortly after leaving Bellaire, the route passes through a large Cut as the creek bends to the south briefly. As the route heads west along the creek, SR 149 passes through several unincorporated communities including Neffs and Glencoe. In Warnock, SR 149 meets and shares a short concurrency (signed as a wrong-way concurrency) with SR 9. Continuing west, the route enters Belmont as Main Street and reaches SR 147 at Jefferson Street. The two routes continue west on Main Street, make a left turn onto Bridge Street, and make a right turn at Railroad Street before exiting the village. At an intersection just west of the village, SR 147 and SR 149 end their concurrency; SR 147 continues west towards Bethesda while SR 149 heads north from this point.