Visit Rocky Mountain Arsenal:

The Best Place to View Wildlife in Denver

Updated June 16, 2021

Rocky Mountain Arsenal National Wildlife Refuge, a mouthful of a name and often shortened to RMANWR, is the nation’s largest urban wildlife refuge.

At 27 square miles, roughly the size of Manhattan, these 15,000 acres of open prairie were once home to the Plains Indians. Today this monster swath of open space still feels like a hidden gem tucked between Denver International Airport and Interstate 70, a major east-west artery cutting across the United States.

Despite its proximity to the everyday surge of commuter traffic, it’s one of the few truly quiet places within the Mile High City and an amazing spot to view wildlife not far from the downtown core.

Rocky Mountain Arsenal History

In the mid-20th Century, Rocky Mountain Arsenal was used as a chemical weapons manufacturing and testing facility and has since undergone a massive cleanup that spanned more than 20 years. 

Following the attack on Pearl Harbor, the US Army purchased the land and created a manufacturing facility to test and produce chemical weapons, including Sarin gas, mustard gas, and napalm. Later the site was leased out to private manufacturers to produce pesticides. A deep injection well for storing chemical waste was constructed in the early ‘60s but discontinued due to the triggering of earthquakes in the area.

Due to extensive soil and groundwater contamination, Rocky Mountain Arsenal was designated a Superfund site by the EPA in the 1980s. As the cleanup of the site began, nesting bald eagles were discovered, which ultimately led to its designation as a wildlife refuge in 1992.

Things to do at Rocky Mountain Arsenal National Wildlife Refuge

Catch and release fishing, hiking, wildlife viewing, birding, photography, and an absolutely gorgeous wildlife drive are among the best things to do and see at Rocky Mountain Arsenal. Make sure to stop in the Visitor’s Center, which features a stuffed bison on display along with historical photographs and displays documenting the Arsenal’s role during WWII.

Do I Have to Pay to Get into Rocky Mountain Arsenal?

Entrance to Rocky Mountain Arsenal National Wildlife Refuge is 100% FREE! The refuge is open from sunrise to sunset, and there are no parking fees or permits required to access the various trails. 

If you’re bringing kiddos, check the hours for the Visitor’s Center beforehand as you won’t want to miss some of the cool interactive displays.

Can You Drive Through Rocky Mountain Arsenal?

Visitors can drive through certain designated areas within Rocky Mountain Arsenal, including a bison viewing area and an 11-mile one-way wildlife loop that is absolutely worth the time. There are a few side roads and trails that are off-limits, but they are clearly marked. 

An important note for cyclists: bicycles are not permitted on the wildlife loop, which I assume is due to the free-roaming wild bison.

Rocky Mountain Arsenal Wildlife Drive

As cool as it is to view all the deer, bison, and prairie dogs here at the Refuge, there’s more to see on this 11-mile loop, including one spooky bomb shelter left over from its days as a testing facility. Visitors are not permitted to enter the small structure, but if you’re brave enough, you can try to peek through the broken glass windows.

Photographs and text by Elaine Skylar Neal / Travels and Curiosities

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