The B1448 follows the pre-bypass route of the A168 through Thirsk.
The road starts at a south-facing limited-access GSJ at the southern end of Thirsk bypass. It heads north across open country, soon going over the East Coast Main Line and then reaching the edge of town. After going through the suburb of Sowerby we reach a mini-roundabout on the A61 on the edge of Thirsk town centre.
There's a multiplex east along Westgate and Castlegate and into the Market Place, where the road regains its number by turning left just before the clock. We now head north past the church, after which the road becomes rural surprisingly quickly. We follow the valley of the Cod Beck upstream and then end by a golf course at a T-junction back on the A168, which is dual-carriageway here to aid the junction.