Rocky Mountain Arsenal Wildlife -Harpers Pond

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Rocky Mountain Arsenal

Just 10 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.


The history of the Rocky Mountain Arsenal National 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 385,000 visitors have explored this unique and beautiful area.


The bison are back! Centuries ago, bison herds roamed this shortgrass 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 shortgrass prairie just outside of Denver.


See some wildlife that is next door to the city! Wildlife you may see on the tour includes bison, coyotes, raptors, mule and white-tailed deer and many song birds. Reservations are required. 


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 include large-mouth 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. Fishing is permitted on Tuesdays, Saturdays and Sundays from 6:00 a.m. to 6:00 p.m. Note: the fishing program is "catch-and-release."


Begin your visit at the Visitor Center, located inside the Refuge entrance, open Wednesdays through Sundays 9 a.m. - 4 p.m. (closed on federal holidays). An interactive exhibit hall takes visitors on a journey through the site's history and showcases the abundance of wildlife at the site. A colorful Discovery Room full of wildlife activities, seasonal crafts and hands-on displays gives young naturalists a whole new perspective on nature.

At the Visitor Center information desk, friendly staff and volunteers can answer your questions, help you choose a hiking trail, and get you better acquainted with the Refuge and visitor opportunities. Nature's Nest Books & Gifts operated by Friends of the Front Range Wildlife Refuges is also located inside the Visitor Center.

REFUGE HOURS: Open daily from sunrise to sunset and is closed only on Thanksgiving, Christmas and New Year's Day. The Visitor Center is open Wednesdays - Sundays from 9 a.m. - 4 p.m. (closed on federal holidays). For additional information please call the Visitor Center at 303-289-0930.

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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