The Jim Gatchell Memorial Museum is a regional history museum in Buffalo, Wyoming. When pharmacist Jim Gatchell opened his drugstore in 1900, it had an immediate impact on the Johnson County community. Before his arrival in Buffalo, Gatchell had grown up on a Lakota Sioux reservation. Because of this and his caring nature, he became a trusted friend of the region's Native Americans. They brought him many gifts, and as word spread, friends and acquaintances began donating mementos of historic people, places, and events from Johnson County and the Powder River region. After Gatchell's death in 1954, his family donated his collection to Johnson County with the provision that a museum be built to house it. The museum opened its doors in 1957 and became a nationally accredited museum in 2002.