[3] The Cascade Canal begins at Fourmile Lake, located 5,748 feet (1,752 m) above sea level.
[4][5] At the edge of Rye Spur, the canal curves right forming a half-circle of about 0.5 miles (0.80 km) radius, then travels northwest until it meets Ursa Creek.
At Ursa Creek, it turns sharply southwest, along Mount McLoughlin's flanks.
The canal is crossed by the Pacific Crest Trail and Oregon Route 140 near the Cascade Divide.
[4][6] It crosses the divide directly between Mount McLoughlin and Brown Mountain, before descending to Fish Lake, at an elevation of 4,639 feet (1,414 m).