Special Alert
The Rocky Mountain Arsenal National Wildlife Refuge is now home to over two dozen bison
The Rocky Mountain Arsenal National Wildlife Refuge is now home to over two dozen bison
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Rocky Mountain Arsenal

Just ten minutes northeast of downtown Denver, the Rocky Mountain Arsenal National Wildlife Refuge (RMA) is one of the most fascinating ecological sites in the country. It’s made a remarkable recovery from a toxic piece of land to a fully rehabilitated natural wonder.

From Chemical Weapons to Wildlife Refuge

The history of the Rocky Mountain Arsenal Wildlife Refuge stretches back more than 60 years. In 1942, during World War II, the U.S. Army bought 17,000 acres of farmland outside of Denver to develop chemical weapons to be used as a war deterrent. After the war, Shell Oil Co. acquired the land and began producing agricultural chemicals, continuing until 1985. There were few environmental laws before the 1960s, and chemical production at the Arsenal resulted in contamination of soils and groundwater at the site. In the 1980s, the discovery of a large population of wintering bald eagles at RMA kick started the environmental recovery of the site that continues today.

Soon, people realized that despite the contamination of the site, there were extensive and healthy wildlife populations throughout the Arsenal. Deer, prairie dogs, coyotes, and many species of hawks, owls and other birds thrived in the abandoned fields, grasslands and wood lots that had been protected from forty years of urban sprawl and development. In 1992, Congress passed the Rocky Mountain Arsenal National Wildlife Refuge Act, designating the site as a future refuge. Since then, the U.S. Fish and Wildlife Service has managed the site "as if it were a refuge," monitoring wildlife health, restoring native prairie habitats, and providing opportunities for spectacular wildlife viewing and recreation.

In the past two decades, the RMA has quickly become one of the premier urban national wildlife refuges in the United States. Since 1990, more than 383,000 visitors have explored this unique and beautiful area.

Bison at the Rocky Mountain Arsenal

The Bison are back! Centuries ago, bison herds roamed this short grass prairie within the shadow of the Front Range, as evidenced by bison bones found at the Arsenal. Now, bison have returned and are thriving. The Refuge is now home to more than two dozen bison, the first time in more than a century that a wild herd will roam the short grass prairie just outside of Denver.

Visitor Tours

See some wildlife that is next door to the city! This two-hour guided tour is available each Saturday, Sunday and Wednesday except for holidays, starting at 10 a.m. Wildlife you may see on the tour includes bison, coyotes, raptors, mule and white-tailed deer and many song birds. Reservations are required - call 303-289-0930.


The RMA Sport Fishing Program has been extremely popular for anglers, providing a serene natural setting and a great "catch" rate of more than one fish per hour during the past 10 years. Game fish in Lake Mary includes largemouth bass, channel catfish, white and black crappie, bluegill, and yellow perch. Grass carp are present in Lake Mary to control vegetation growth and common carp are present in both lakes. Note: the fishing program is "catch-and-release."

Kids Activities

Every first Tuesday of the month at 10 a.m., the Rocky Mountain Arsenal offers a fun and free one hour program for your young naturalist, ages 2 to 5 years old. Your little ones will be able to explore the refuge, while learning about the natural wonders that surround them. Kids will also love the Visitor Center Learning Lab where they'll discover what grows, creeps, crawls, hops, swims, flies and slithers on the Refuge. With hands-on activities and displays, it's a perfect spot to spend an hour or two. Note: Parent or guardian must accompany all children. Call 303-289-0930 for more information.

REFUGE HOURS: 6 a.m.-6 p.m. Tuesday, Wednesday, Saturday, & Sunday. Visitor Center Hours: 7:30 a.m.-4:00 p.m. Tuesday, Wednesday, Saturday, & Sunday.

DIRECTIONS: The Refuge is 11 miles northeast of Denver. From I-70 take the Havana Street exit north to 56th Avenue. Proceed forward through the gate and follow any posted directions.

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