 Gilmore was named Custodian of Fossil Reptiles in 1908, and settled in the Park View neighborhood at 451 Park Road, NW.In 1923 Gilmore and Boss collected a "Diplodocus longus" in Dinosaur National Monument, Utah.Under Gilmore's direction, the specimen was mounted and displayed at the National Museum of Natural History in 1931, where the specimen proved the museum's most popular exhibit for the next 20 years.