Rainbow Falls is a 28-foot waterfall on the South Branch Grass River in St. Lawrence County, New York, on state land in the Town of Clare off Tooley Pond Road. It is the uppermost of the major falls on the South Branch, and a short woods walk leads to its gorge.
The falls
Above the drop the river splits around an island-like mass of rock. The main channel squeezes into a single steep chute about 25 feet wide and falls into a narrow gorge walled by sheer cliffs, while a side channel skirts the falls over boulders without forming a waterfall of its own. The drop is 28 feet, surveyed in person; earlier surveys listed 35 feet. The river drains a basin of roughly 118 square miles of lakes and wetlands, so it keeps flowing all year.
Getting there
The falls sit in the DEC's Grass River Complex. The falls are 6.1 miles out Tooley Pond Road from its junction with County Route 27 near Degrasse; from Tupper Lake, drive 27 miles on Route 3 toward Cranberry Lake, then 11 miles on Tooley Pond Road, watching for a small sign on a tree beside three large boulders on the left. Parking is along the road. The path is 0.3 mile unmarked and unmaintained; the round trip is 0.6 mile with about 70 feet of gain, rated easy. A February 2024 DEC work plan proposes a four-car parking area here.
When to go
Flow peaks with the spring freshet from March to May. On sunny days, rainbows form in the spray, which is the reason for the name.
On site
The path crosses a narrow wooden footbridge over a brook that gets very slippery, and the top of the falls has steep drop-offs; the better views are downstream. In spring runoff anyone standing at the gorge edge can get soaked, and ice builds on the rocks even when the air is above freezing. Microspikes are advisable in winter; caution is needed around frozen and rushing water.
History and name
The whitewater community knows the falls as "Large Marge."
Nearby
The South Branch has a chain of falls within a few miles: Flat Rock Falls is about 1 mile away, Bulkhead Falls about 1.9 miles and Twin Falls about 2.2 miles.
Distances are straight-line.