This article is about the Class III road numbered C675 maintained by DfI Roads. For other roads numbered C675, see C675.
The C675 consists of several different roads primarily based around Castlederg. Starting in Castlederg, the road follows Kilclean Road north and Killeter Road west out into the countryside. To the north the road climbs gradually until it reaches the border. The road itself continues as the R235 to Castlefinn, County Donegal. This segment of the route was formerly part of the B50 and was downgraded during the 1970s. In the west of Castlederg a spur turns off north west along Cavan Road, climbing up towards the border at Carn Hill just after turning sharply northwards. Beyond the border the road continues into County Donegal and eventually reaches Killygordon. Following Killeter Road, the route follows the River Derg on its northern bank and features another spur heading west initially before it TOTSOs north west to a crossroads. From here the spur continues south across the Mourne Beg River and crosses the main component of the route before ending at a T junction on the C674 near Killeter on the other side of the River Derg. A crossroads is soon reached and the road TOTSOs north, soon making its way north westwards in a fairly consistent manner. The C road stops short of yet another interaction with the border by a few kilometres, for the remainder of the road to the border is unclassified.