John Jacob "Jay" Barnhill, 62, of Mills, Wyoming, was last seen on September 10, 2019. Barnhill told his live-in girlfriend he was leaving to run errands and sent her several text messages after leaving the house, but he never returned. His girlfriend reported him missing on September 12, 2019. On September 14, 2019, Barnhill's pickup truck was found off the roadway near Sheepherder Hill on Casper Mountain, in the area of Casper Mountain Road and Manly Road in Natrona County — a sparsely populated area surrounded by private property and land owned by the Bureau of Land Management. The truck had been driven through brush and parked well off the roadway; there was no sign of Barnhill at the scene. Barnhill is a white male, 5'11" and 185 pounds, with long graying black hair he wore in a ponytail secured with multiple hairbands, a gray mustache, and brown eyes. He normally wears glasses but left them at home. He has a white scar on the right side of his torso near the ribs and a large mole on his back near the right shoulder blade. He was last seen wearing a long-sleeve "Bone Daddy" T-shirt, blue jeans, white sneakers, and a silver wristwatch on his left wrist.
The Mills Police Department is the lead investigating agency, assisted by the Natrona County Sheriff's Office. In the weeks following Barnhill's disappearance, searchers covered a roughly six-mile radius around Sheepherder Hill and Muddy Mountain — encompassing most of Casper and Muddy Mountains — before deteriorating weather and snow cover suspended the ground search in October 2019; no trace of Barnhill was located. The case is documented in NamUs (#MP60982) and in the Wyoming Division of Criminal Investigation's NCIC-based missing-persons database. The Mills Police Department publicly renewed its appeal for information in June 2026 and again in August 2026, stating it had received new information and asking anyone with knowledge of Barnhill's disappearance to come forward. The case remains open and unsolved. Anyone with information is asked to contact the Mills Police Department at 307-235-8278 (Detective J. Marin, 307-251-1198) or Crime Stoppers at 307-577-8477.