The Barnsdall Main Street Well (also known as Indian Territory Illuminating Oil Company Well #20 Osage County) is an oil well in the middle of Main Street in the town of Barnsdall, Oklahoma. It is believed to be the only such oil well anywhere in the world. It was listed on the National Register of Historic Places on October 1, 1997 as part of the "Energy Related Resources in Northeastern Oklahoma Multiple Property Submission".