Ground-water levels at selected wells in St. Croix, the largest of three U.S. Virgin Islands, were monitored from 1969-73. Continuous recording instruments were installed at Mahogany, Castle Coakley, Airport, and Adventure wells, in central St. Croix. Monthly observations of instantaneous ground-mater levels were also made at two wells near Barren Spot and River Gut. Precipitation data from National Weather Service stations near the Mahogany, Airport, and Castle Coakley wells are shown with the water-level data.