Hydrologic data were collected from the Tamarack Ranch Wildlife area and vicinity near Crook, Colo., during the period September 1979 to August 1981. These data will aid in the analysis of the effects of proposed water-development projects on the hydrologic system of the wildlife area. The data collected included a reconnaissance evaluation of specific conductance, a 24-hour sampling of air and water temperature at 6 sites, and periodic measurements of water levels, temperature, and specific conductance at 57 sites.