The Oregon Trail Museum Association (OTMA) is a non-profit organization which operates the bookstores at Scotts Bluff National Monument and Agate Fossil Beds National Monument. Each year the Association donates a major portion of their profits to the monuments, which assists in interpreting the human and natural history of this area to visitors.

Since 1956, OTMA has continually provided support services for both Scotts Bluff and Agate.