Measuring in at 15,000 acres, the Rocky Mountain Arsenal is one of the largest urban national wildlife refuges in the nation, and it comes with a rather sordid history. The site opened in 1942 as a chemical weapons manufacturing center, and was operated by the U.S. Army until 1992 — shortly after bald eagles—formerly endangered—were discovered on the premises. “That was the impetus for designating the land as protected,” explains Visitor Programs Supervisor Cindy Souders. By 2004, a refuge was formally established by act, and site clean up commenced. “Eagles still roost here for the winter,” Souders says, estimating that the Arsenal hosts up to 80 annually.

Raptors aren’t the only ones flocking to this haven: More than 300,000 humans come each year, too, to observe some 330 species of wildlife safeguarded by the U.S. Fish & Wildlife Services. “We”re primarily short and mixed grass prairie, but we also have wetlands and wooded habitat,” Souders says. Families can access these distinct dwellings on a 9-mile self-guided auto tour, or by foot.

Along the Arsenal’s 10-mile system of linked, kid-friendly trails, observant explorers spy white-tailed deer, bison, monarch butterflies and burrowing owls nesting in abandoned prairie dog tunnels. Anglers of all ages are invited to try catch-and-release fishing at lakes Mary and Ladora between April and October for $3 per day. The refuge is also a pit stop for migratory songbirds such as bluebirds, and in celebration of Migratory Bird Day, the Arsenal hosts free programming on Saturday, May 14.

Grab an activity backpack at the visitor center before your adventure begins; packs come fully loaded with nature games and discovery tools, and a scavenger hunt is available, too. No need to rush outside, though — children love exploring the visitor center’s exhibits on prairie wildlife and plants, and the full-sized bison taxidermy mount offers a fun photo opp.

A nearby discovery room was constructed with wee environmentalists in mind, with interactive displays, hands-on learning stations, microscopes, a puppet theater and animal-themed arts and crafts that transform with the changing seasons. Owl pellets are available for dissection at certain times of the year, and a young explorer zone is where toddlers can unwind with a book or blocks. “Youth,” says Souders, “are our conservation future. We do everything we can to create and build conservation connections.”

Check it Out

Located at 6550 Gateway Road, Commerce City

fws.gov/refuge/rocky_mountain_arsenal

Need to Know

The refuge is open daily from sunrise to sunset, except on Thanksgiving, Christmas and New Years Day. Federal holidays aside, the site’s visitor center welcomes guests Wednesdays through Sundays, 9 a.m. to 4 p.m.

Admission

Free

Best Kept Secret

Don’t miss the black-footed ferret exhibit, located near the visitor center. Paying homage to one of the most endangered species in North America, this special attraction allows kids to get up close and personal with two live ferrets.

Up and Coming

Endangered Species Day on May 20 heralds an exciting line-up of programming; check the website for details.