It begins a little to the northwest of St John's Town of Dalry, at the point where the southeast-bound A713 bears left to cross the Water of Ken to reach the town. The A762 turns off at this corner to remain on the right bank of the river. It soon reaches New Galloway, where it crosses the A712 at a crossroads where the priorities are such that through traffic on both roads has to TOTSO.
A couple of miles further on, the river widens out into Loch Ken and the A762 is squeezed into the strip of land between the loch and the wooded hill to the right. Presently, however, the lochside curves whilst the A762 continues ahead to climb up into the wood. The Black Water of Dee is crossed before the road runs alongside Woodhall Loch (on the right this time) and then reaches Laurieston where the B795 (towards Castle Douglas) turns off to the left.
A couple of miles of surprisingly flat land follow before the road winds between a couple of hills and reaches Ringford and a T-junction. This is the original line of the A75 but now that the village is bypassed the A762 TOTSOs right to take the pre-bypass line to another T-junction on the present A75. There is a multiplex to the right for a mile or so before the A762 turns left to regain its number and heads south for another couple of miles. As the road reaches the estuary of the River Dee it bears round to the left. The road ends at another T-junction on a sharp bend, this time on the A711 adjacent to the Tongland Bridge over the Dee.
The two sections of the A762 were unclassified when the UK's roads were numbered in 1922. The sections of road were soon upgraded, however, being numbered as the A762 by the early 1930s.