The OS Museum was built to house the art and artifact collection gathered from around Texas and the world by the late Mr. and Mrs. Giles McCrary of Post. The museum's current owner is the founder of the OS Ranch Foundation, Giles Connell McCrary, whose grandfather was an early proprietor of the nearby ranch for which the museum is named. But the museum's exhibits range much further in scope than the OS Ranch itself. During Easter, for instance, eggs by Fabergé, Waterford Crystal, and Lalique are displayed. Christmas exhibits include nativity scenes, crèches, ornaments, brass statues, and sculpture. The museum includes the works of many artists of the Southwest who have depicted Texas in the late 19th and early 20th centuries.The gallery is located in the room that was designed as the meeting room for the community, in the building C. W. Post built in 1911 as offices of his Land and Cattle Company.