Located in Beaver County about 15 miles west of Beaver via SR-21. Includes a county campground and paved launch ramp.
Here is the description from the Utah DWR:
Minersville Reservoir is located about 15 miles west of I-15 after exiting at Beaver, Utah. This is just over a three-hour drive from either Salt Lake City or Las Vegas. The reservoir is over 900 acres in size when full. A county operated campground and paved boat ramp are available for public use. Much of the shoreline is BLM administered land and open to the public, although there is some private land that is closed.
The fishery at Minersville Reservoir is managed to produce trophy-sized trout. Special fishing rules apply, which include the use of flies and lures only and a restricted harvest of only 1 trout over 22 inches in length. These rules were established in the early 1990s to correct biological problems and maintain a quality fishery. Prior to the 1990s, high numbers of Utah chubs competed with trout for food and space.
In addition, predation on trout by fish-eating birds was a problem that limited the fishery. Expensive chemical treatments with rotenone were repeatedly conducted to temporarily solve problems and re-establish a trout fishery. This proved to be ineffective because good fishing only lasted about three years, and treatments were needed at least every five years. The new management plan successfully produced good fishing throughout the 1990s without the need for rotenone treatments. Although harvest of trout is now restricted, good numbers of trout are now maintained despite chubs and birds (as long as water is available).
The fishery rebounded after the drought in 2005, but lower water levels and poor water clarity in 2007 and 2008 led to a decline in fish condition. Better water levels mean that the trout fishery should rebound again. Anglers have caught a lot of 18- to 20-inch fish in recent years. Shore fishing, boat angling and float tubing are all popular on this reservoir.
Early in the season, from early-March through April, mature trout look for a spot to spawn, so fishing close to shore is effective. This time of year, shore anglers casting jigs or spinners can be just as successful as anglers fishing from tubes or boats. When the water temperatures warm, fish move into deeper portions of the lake and shore fishing becomes less effective. Even in midsummer, however, trout can occasionally be caught near the shore in the late evening or early morning.
If you are looking mainly for recreation and like the idea of landing some exceptional trout, keep Minersville in mind for at least the next few years. Anyone who spends a little time at this reservoir will likely catch a 20-inch trout, and maybe a few smallmouth bass as an added bonus.