Location
Grassy Lake is located in Sanpete County, Utah and is part of the Manti-La Sal National Forest. From Joes Valley Reservoir take UT-29 west past the Joes Valley Campground for 4.7 miles. Look for the Grassy Lake sign and turn onto Forest Road 0055. Follow Forest Road 0055 for 2 miles north. The lake will be next to the road and is easy to see.
Fish Species
Around 2500 rainbow trout are typically stocked each year. The rainbow trout are stocked four times a year with at an average length of 10". Around 2500 tiger trout are typically stocked once a year at an average of 4.5".
Other Info
When I was last here in the summer of 2019 there wasn't much cell phone signal in the area. If you need to make a call check out Forest Road 2155 which is about a mile south of Grassy Lake. The road goes up a small hill which looks out over Joes Valley Reservoir. The view is very beautiful and you should be able to get a decent signal, There are several spots to camp below the lake off Forest road 0055. If you have a trailer I would avoid going past the lake as the road gets rough pretty quick.
History
In 1937 Cottonwood Creek Consolidated irrigation company put fourth a proposal for construction. In the proposal a ditch would lead from Blue Lake #3 to Grassy Lake and would exit into the Littles Creek which is a tributary to Cottonwood Creek. In 1945 there was further construction on the dam. In 1974. the forest service oversaw a project to reconstruct the dam. This project turned the lake into a constant level fishery so the fish wouldn't suffer winter kill.
Nearby places to Fish
Blue Lake 3 (Jewkes) is one mile north on Forest road 0055. Littles Creek flows from Blue Lake into Grassy Lake then flows into Joes Valley Reservoir to the east. Other nearby spots include Mary's Lake, Soup Bowl Reservoir, Petes Hole Reservoir, Academy Mill Reservoir, and Potters Pond.