The Rattlesnake Hills gas field, located in eastern Washington, is an unusual occurrence of natural gas at extremely low pressures, but in commercial amounts. It produces a high methane type of gas from 16 wells completed in one or both of two zones of porous basalt flows capped or intercalated with shales. The original well pressure, taken at the casinghead, as nearly as can be determined, was slightly more than 2 pounds, but present field pressures average slightly less. The daily capacity of the wells, as of October 2, 1930, ranged from 25 to 1.5 million cubic feet, and the entire open flow of 10 wells, then constituting the field, was about 5,190,000 cubic feet. Sales of gas in October, 1903, averaged 368,000 cubic feet daily. The field lies on a northeast plunging an icline developed on the north flank of a major northwest-southeast trending belt of anticlinal folding, known as the Rattlesnake range of hills.