As early as 1901, State Geologist Samuel Calvin cautioned those who were “… ready to stake their own fortune and that of their nearest friends on the belief that oil and gas are everywhere underneath the surface.”
Efforts to coax oil from the ground in Iowa have included exploding nitroglycerine to induce oil flow, salting with crank case oil to induce investors, using radar salvaged from a World War II bomber, and visions of a psychic from Massachusetts.
Of the 123 known exploration wells in Iowa, just three have yielded oil, all in Washington County. Others have yielded encouraging signs and valuable information. The state’s first show of oil was from a well in Fremont County in 1925. The deepest oil test yet drilled was to 17,851 feet in Carroll County in 1987, and while no petroleum was found, thick black
shales suggest past formation and migration of potentially large volumes of oil.
The best prospects for oil in Iowa are in: 1) southeast Iowa where local structures may have preserved small quantities of oil that migrated from the Illinois Basin in southern Illinois; 2) southwest Iowa, which includes the northern limits of the Forest City Basin (centered in northwestern Missouri); and 3) the deep flanks of the Midcontinent Rift, a 100-mile-wide belt from the central Minnesota border to the southwest corner of Iowa.