Reservoir E is a small lake located within Riverdale Regional Park at the Adams County Fairgrounds, just northeast of the Denver metro area in Adams County, Colorado. Situated along the South Platte River corridor, this urban reservoir offers fishing, walking trails, and open space within easy driving distance of Commerce City, Brighton, and Henderson. The lake hosts community fishing events, including the Adams County Seniors Fishing Tournament organized by the Adams County Sheriff, making it a welcoming spot for anglers of all ages and skill levels.
Fishing is the primary water activity at Reservoir E, with bank fishing access along the shoreline. The annual seniors fishing tournament draws a crowd each year for a morning on the lake in a relaxed, community-focused setting. The reservoir sits within the broader Riverdale Regional Park, which features miles of paved and unpaved trails along the South Platte River, old-growth cottonwood groves, and views of the Riverdale Golf Course. Visitors have noted a decommissioned vessel on the lake known as the Colorado Battleship, which offers a bit of local history worth checking out during a visit.
Hiking, biking, and walking trails wind through the park and connect to the larger South Platte River trail system, creating options for longer rides or runs along the Front Range. The park grounds are well maintained with ample free parking on non-event days, open green space, and picnic areas suitable for families. Bird watching along the river corridor and cottonwood stands is a quiet activity available year-round. The park also features a disc golf course for a free round between trail sessions.
The Adams County Fairgrounds share the property and host events throughout the year, including the Adams County Fair, car shows, craft fairs, holiday markets, and community expos. During major events, parking costs twenty dollars and congestion can be significant, with long waits entering and exiting the grounds. On regular days, the park is quiet with generous parking and easy access. The fairgrounds include exhibit halls, barns, and event spaces available for private and public gatherings.
Seasonal considerations matter at Reservoir E. Summer brings fair events and fishing tournaments, while fall and winter offer quieter trail conditions and holiday craft fairs. Food vendors are typically available only during fair events and may not open until late afternoon. No swimming or motorized boating has been documented at the reservoir. The park is open year-round and serves as one of the better urban green spaces along the northern Front Range, combining water access, trail networks, and community event space in a single location accessible from multiple Denver-area highways.