Rainbow Falls is one of the tallest waterfalls in the park and definitely one of the most photographed. On a hot day lingering near the base will give you a very cooling mist. Spring time hiking gives the best opportunity for heavy water flow and a rainbow. Be sure to read the link about the trailhead.
Important additional information
Dogs are absolutely prohibited in this game preserve.
Primary Trailhead: This is part of the St Huberts parking area/trailhead. Leave Lake Placid on Route 73, follow Route 73 toward Keene. Continue through Keene and Keene Valley and into Saint Huberts. Continue to the trailhead for the AMR on the right, directly across the road for the Roaring Brook Falls Trail to Giant Mountain. This is approximately 3.0 miles from the outskirts of Keene Valley. This is a 9.4 mile hike, round trip, along a woods road and well maintained foot trail.
From the parking lot you will initially have to follow a dirt road to a paved road next to a golf course. At 0.5 miles from the parking area, turn left and down between two tennis courts on Lake Road Way to get to the gate into the AMR. The AMR is a private property area with recreational easements, special rules apply to use and those are posted at the gate. At the gate you will need to hike the dirt access road for a bit over 3.0 miles to Lower Ausable Lake. This dirt road is referred to as Lake Road and is just that. The road climbs steadily to the dam. There are other trails to get you there, but using the road is the most efficient. At the dam, cross the bridge below the dam and follow signs to the right turn off the Gothics trail to Rainbow Falls.
At this point the trail becomes a bit difficult and very slippery in spots. The footing is a bit difficult and families with younger kids should just take their time and be cautious. You will be following along the stream that leads through a deep canyon with rock slopes and steep side that leads to the base of the falls and as you get closer you will hear it and eventually feel the spray.
Family with Young Kids: Primary trail – 5 to 6 hours, RT
Experienced Hiker: Primary trail – 3 to 4 hours, RT
Out of Shape Hiker: Primary trail – 4 to 5 hours, RT