The refuge is on the grounds of the former Rocky Mountain Arsenal, a United States Army chemical weapons manufacturing facility.

The site was designated a national wildlife refuge in 1992 by the United States Congress, and underwent a costly environmental cleanup in order to remove pollutants.

More than 330 species of wildlife inhabit the refuge, including raptors, deer, raccoons, coyotes, white pelicans, black-footed ferrets, black-tailed prairie dogs, and bison.

[1] In 1986, while environmental testing was continuing, a winter communal roost of bald eagles, then an endangered species, was discovered at the Rocky Mountain Arsenal.

[4] Congress enacted the Rocky Mountain Arsenal National Wildlife Refuge Act on September 25, 1992, and the legislation was signed into law by President George H. W. Bush on October 9.

[5] At the time the refuge was established, the RMA consisted of more than 17,000 acres (69 km2) of grassland dotted with small manmade lakes and ponds.

[5] The former Shell Oil Company land also proved to be a problem, as it was somewhat geographically isolated from the rest of the refuge and not likely to be used by wildlife as habitat.

On January 21, 2003, the Environmental Protection Agency (EPA) certified 940 acres (3.8 km2) as ready for use, and this acreage was turned over to the USFWS.

[9] This allowed USWFS to formally open the Rocky Mountain Arsenal National Wildlife Refuge on April 2, 2004.

[16] About two-thirds of the refuge consists of mixed-grass and shortgrass prairie, while the remainder is a mix of forest, shrubland, and lakes, streams, and riparian areas.

A large number of man-made features dot the landscape, including irrigation ditches, lakes and ponds, and former homesteads.