This article is about the Class III road numbered C251 maintained by DfI Roads. For other roads numbered C251, see C251.
The C251 is a class III road in north Down. It starts on Church Street (A20) in Newtownards near Ards Community Hospital and heads north along William Street and Crawfordsburn Road out of the town. Soon the road meets the B170 on a corner just south of the A2 junction. The road resumes from the A2 in a northward direction, meeting the B20 in Crawfordsburn to the west of Bangor.