There were no relatively important oil and gas discoveries in the Rocky Mountain region in 1939 in unproved areas. One well in the southwest Pondera or Pendroy district, Teton County, Montana, produced a little oil from the Madison limestone, but was considered non-commercial and was saved as a gas well in the Colorado shale. The only other discovery in an unproved area was a relatively small gas well on the Horne Valley anticline, Carbon County, Wyoming, less than ½ mile southeast of a stratigraphically deeper dry hole.

The deepening of oil wells farther into the Tensleep sandstone resulted in relatively large oil production in the old Wertz gas field, Carbon County, Wyoming. In the Lance Creek field, Niobrara County, Wyoming, a rather widespread and prolific oil zone was found in the Minnelusa sandstone as much as 200 feet below the oil-producing Leo sand; and in the old Fort Collins field, Larimer County, Colorado, a well deepened to the second sand of the Dakota group tested about 300 barrels of oil and some water daily.

Extensions to old fields included the completion of three oil and gas wells and one gas well in the Sunburst sand member of the Kootenai formation in the North Cut Bank field, Glacier and Toole counties, Montana, one well testing as much as 43 million cubic feet of gas daily. At the north end of the main oil-producing part of the Cut Bank field and downdip slightly from 3 near-by oil wells the Sunburst sand yielded the largest gas well yet discovered in Montana--80 million cubic feet per day. Southeast of the town of Cut Bank, the oil field was extended eastward about 1 mile to about its east limits, and one well extended the north limits of the oil field about 3/4 mile.

At Lance Creek, Wyoming, Sundance sand oil production was extended more than one mile east in 1939 to a point slightly more than 4½ miles east northeast of the present west limits of the field. At Wilson Creek, Rio Blanco County, Colorado, Morrison sand oil production was extended slightly more than 1 mile northwest by the completion of the second oil well in the field.

Wildcatting was very much restricted throughout the region in 1939. One wildcat well is shut down near Pinedale, Sublette County, Wyoming, at a depth of 10,000 feet and another was abandoned at Divide Creek, Mesa County, Colorado, at a depth of 10,815 feet, being the deepest well yet drilled in the region. In addition, there were only 6 other really important wildcat wells completed in the region in 1939.

The only important pipeline constructed in the Rocky Mountain region in 1939 was the 438-mile line laid between Fort Laramie, Wyoming, and Salt Lake City, Utah, by the Utah Oil Refining Company.