Gunlock Reservoir is located to the northwest of Ivins, off of Old Highway 91. It is a primitive area, with only a couple bathrooms, although the park offers a variety of activities, including camping, swimming, boating, and fishing. The reservoir has a reputation of producing large, hard-to-catch bass, and many anglers prefer flyfishing at Gunlock to Sand Hollow Reservoir or Quail Creek Reservoir, which are more popular.
Because Gunlock is at a slightly higher elevation than the other Washington County reservoirs, the water temperature remains cooler than other lakes in the area.  Gunlock Reservoir also has a smaller surface area and limited access to the one small sandy beach. Those two factors reduce the number of visitors to Gunlock.  Because there are fewer people here, I prefer this lake.  However, if you come on a Saturday and there are already more than 3 or 4 boats on the water, you might as well turn around because it is dangerous and stressful to navigate such a small lake when there are so many watercrafts on it.

If you want to camp or drive to the beach, there is a secret road that allows you to access the sandy beach with a 4x4 truck.  You will see it if you look at the lake on Google Earth.