Two test wells were drilled in the upper Satus Creek basin of the Yakima Indian Reservation, Washington, using the air-rotary method. At site 1 the well penetrated a young basalt and 175 feet of the Yakima Basalt, and at site 2 the well penetrated the young basalt. The well at site 1 was drilled to a depth of 350 feet. Tests for drawdown and yield indicated a specific capacity of about 11 gallons per minute per foot of drawdown. The potential yield of this well may be about 1,000 gallons per minute. The well at site 2 was drilled to a depth of 500 feet. Only a small quantity of water was encountered and no test for yield was made. Data from these wells, including chemical analysis of the water from the well at site 1, will provide information useful in the development and management of the ground-water resources in this part of the Yakima Indian Reservation. (Woodard-USGS)