The name Trinity Mountains refers to a rugged North/South ridge line that runs from Dog Mountain (just above Anderson Ranch Reservoir) to Sheep Mountain (just north of the Middle Fork Boise River). The name was used by miners but has not been officially adopted by the government. Trinity Mountain (9,451 feet) is the highest point on the ridge. Other notable summits include Peak 9165, Peak 9140, Fiddlers Perch, Peak 9037 and Peak 8554.
The ridge is accessed by the Trinity Mountain Road [(E)(2.2) on Page 155] which climbs as high as 8,400 feet as it traverses the range from south to north. A 4WD is recommended. Much of the Trinity Mountain area was burned by a forest fire in 2012. Still, there are living trees to be found and the many high mountain lakes around Trinity Mountain provide good camping.