The C451 runs along the south side of Loch Tay. It starts on the A827 at Kenmore, and immediately passes the hill road over to Glen Quaich. A little further along, the Scottish Crannog Centre sits on the lochside, next to the marina complex. Beyond this, the road quickly becomes more rural, winding along the lochside through fields and past scattered houses. The tiny villages of Acharn and Ardtalnaig are passed through before the route comes to an end at the council boundary, just before Ardeonaig. The road itself continues the full length of the loch to Killin at the western end.