The Marfa lights are often visible on clear nights between Marfa and Paisano Pass in northeastern Presidio County as one faces the Chinati Mountains. At times they appear colored as they twinkle in the distance. They move about, split apart, melt together, disappear, and reappear. Presidio County residents have watched the lights for over a hundred years. The first historical record of them recalls that in 1883 a young cowhand, Robert Reed Ellison, saw a flickering light while he was driving cattle through Paisano Pass and wondered if it was the campfire of Apache Indians. He was told by other settlers that they often saw the lights, but when they investigated they found no ashes or other evidence of a campsite. Joe and Sally Humphreys, also early settlers, reported their first sighting of the lights in 1885. Cowboys herding cattle on the prairies noticed the lights and in the summer of 1919 rode over the mountains looking for the source, but found nothing. World War I observers feared that the lights were intended to guide an invasion. During World War II pilots training at the nearby Midland Army Air Field outside Marfa looked for the source of the elusive lights from the air, again with no success.
Those who have viewed the lights over a long period personify them and insist that they are not only harmless but friendly. Mrs. W. T. Giddings, who grew up watching the lights and whose father claimed he was saved from a blizzard when the lights led him to the shelter of a cave, considers the lights to be curious observers, investigating things around them. Over the years many explanations for the lights have been offered, ranging from an electrostatic discharge, swamp gas, or moonlight shining on veins of mica, to ghosts of conquistadors looking for gold. The most plausible explanation is that the lights are an unusual phenomenon similar to a mirage, caused by an atmospheric condition produced by the interaction of cold and warm layers of air that bend light so that it is seen from a distance but not up close. In recent years the lights have become a tourist attraction. The Texas Department of Transportation constructed a roadside parking area nine miles east of Marfa on U.S. Highway 90 for motorists to view the curious phenomenon. The Marfa Mystery Lights Viewing Center was built at that site in 2003.