|Length:||11.7 miles (18.8 km)|
|Meets:||A172, B1257, B1292, A171, B1269, B1268, A174|
|Old route now:||B1257|
|Route outline (key)|
The A173 is a reasonably short, largely rural A-road on the northern edge of the North York Moors.
The road originally started on the A172 in the centre of Stokesley. That road now bypasses the village so the A173 has been moved with it and now starts at a roundabout on the bypass; the old road into town is now part of the B1257.
The A173 heads northeastward, skirting the eastern edge of the moors. It passes through the large village of Great Ayton and close to the tourists' favourite, Roseberry Topping. After marking the boundary of the North York Moors National Park for a few miles the road reaches a roundabout on the A171 Guisborough bypass.
The A173 once ran through the town of Guisborough, but now joins and is subsumed into the A171 bypass some 3 km west of the town centre. Resuming its own route after reaching Church Lane on the northeastern edge of the town, the A173 continues through very uneven coastal country to Skelton. It originally ran through town to Brotton where it ended on the A174. When that road's bypass was built the eastern end of the A173 was declassified and the road was diverted along a short stretch of ex-B1267 to meet the bypass just to the north of Skelton.