It did indeed run along what is now called Frogmoor, a road that leads northwards from the Oxford Rd in the town centre to Hughenden. The proof can be found by comparing the names of those listed alongside the "Canal" in the 1851 census, with the 1849 High Wycombe Tithe Map and Apportionments.
The canal would have been formed from the "Hughenden Stream", which still exists, but disappears into a culvert by Morrisons supermarket. It re-emerges opposite the Wycombe Swan theatre, having joined up in the culvert with the River Wye. The river then flows eastwards to Bourne End, where it empties into the River Thames.