Boulder Rapids is a stretch of rapids in Idaho County, Idaho, in the Blue Mountains region. It lies about 27.3 miles west of Grangeville and roughly 121.9 miles east of Pasco as the crow flies.
The Blue Mountains of northeastern Oregon and adjacent states are a group of dissected uplands and volcanic plateaus with ponderosa pine, Douglas fir and grand fir forest and dry grassland on lower slopes. Deep canyons and steep tributaries carry snowmelt streams with waterfalls.
There are 65 recorded rapids in Idaho County. Deep Creek Rapids, is under a mile away. Big Sulphur Rapids, is under a mile away across the state line in Oregon. Dry Creek Rapids, is about 1.1 miles away across the state line in Oregon.
Boulder Rapids is located at 45.7799° N, 116.6485° W. The listing is based on the USGS Geographic Names Information System, one of the sources compiled by the U.S. Geological Survey in its inventory of waterfalls and rapids of the conterminous United States. The position was verified on aerial imagery. Details on trails, parking and access have not been documented for this rapid yet.