Marys Lake is part of the Colorado-Big Thompson Project. There are 2 dikes on the shoreline of Marys Lake, located approximately 2 miles from Estes Park, Colorado. There is a developed campground accommodating 138 campsites, which includes RV and tent camping sites with utility hookups, two full service shower houses, as well as a small convenience store are also located on site. The reservoir has approximately 42 water surface acres, 175 land acres, and 1 mile of shoreline. No boating is allowed. The reservoir is regularly stocked with rainbow trout. A free summer shuttle provides access to Estes Park. Facilities are open May 15- Oct 15th.