Half Marathon races near Niwot

The Westy Half & 5k is a fall running event in Westminster, Colorado, located at 10600 Westminster Boulevard. It features two distances: a half marathon for those seeking a longer morning run, and a 5k for participants preferring a shorter race. The event is part of the Hometown Race Series, which organizes half marathons and 5k races in communities outside the primary Denver and Boulder metro regions. A notable aspect is the 5k medal policy: all 5k finishers receive a medal, a practice that remains infrequent for this race distance.

The Louisville Trail Race offers half marathon, 10K, and 5K distances on dirt trails near Louisville Community Park in Louisville, Colorado. It provides a Front Range trail running experience, allowing both experienced and newer trail runners to select a course suited to their abilities. The routes are predominantly flat and dirt, utilizing an out-and-back structure on trails surrounding the park. A challenging hill near the finish offers views of the Flatirons and Front Range mountains. This event, now in its second decade, maintains a family-friendly atmosphere with post-race activities encouraging participants to bring guests.

The Turkey Trek is a Thanksgiving race series held at Long Lake Regional Park in Arvada, offering four distances: a 13.1-mile Half Turkey, the 10k Turkey Trek, the 5k Turkey Trot, and the un-timed 2k Turkey Toddle. The 5k begins at 8:30 AM MST, with the half marathon starting at 8:40, the 10k at 9:00, and the 2k at 9:10. This staggered start accommodates runners and walkers of various abilities throughout the morning. The course ascends to a summit at the 3-mile point, featuring the Egg Nog Chug Challenge where participants can drink 5 ounces of eggnog for a chance to win a new pair of shoes. Following the exposed upper section, the path crosses a ridge for a mile before descending the mesa's east side. The route then transitions to a flatter straightaway with hay bales for the Hay Bale Hop Challenge. This clockwise loop returns to the park, and approximately one kilometer from the finish line, racers encounter the Fill Your Pie Hole Challenge, involving pumpkin pie before the final push. Half marathon finishers are awarded a mug.

Run Denver 'Mile High City' 5K/10K/13.1 is a local Denver running event offering 5K, 10K, and half marathon distances, taking place in late November. It functions more like a supported group run than a large race: each wave is limited to approximately 15 to 20 participants, both runners and walkers are accepted, and timing chips are not used. The atmosphere is intentionally relaxed. Bibs are distributed on race day, participant gifts are mailed out, and organizers can record times by bib number upon request. Waves begin in the morning and are filled sequentially, with a waitlist or virtual run offered once capacity is reached. Participants receive a shirt, medal, and entry into a virtual runner community; the virtual option also includes text-based coaching support prior to the run.

The All-Out Spring Fever is a spring race held on the Ralston Creek Trail close to Golden, Colorado. Runners can choose between 5K, 10K, and half marathon distances. The courses run alongside Blunn Reservoir in Arvada, offering views of Table Mountain and the Colorado foothills, giving it the feel of a foothills trail run rather than a city race. This event is organized by All-Out Multicourse and serves as the spring complement to their Kooky-Spooky series. The race features a bee mascot named Buzzby, benefits the People and Pollinators Action Network, and offers a chance for participants to qualify for a BOLDERBoulder starting wave. A virtual half marathon option is available for those who wish to complete the distance remotely.

All-Out Beat the Heat takes place in Westminster, Colorado, on the Big Dry Creek Trail near Standley Lake, offering 5K, 10K, and half marathon distances. This is the 15th year for the event, organized by All-Out Multicourse. It also functions as an official BOLDERBoulder qualifier, allowing runners aiming for a seeded start to achieve a qualifying time here. Each distance follows Big Dry Creek Trail southwest. The course is described by the organizer as having moderate terrain, neither excessively hilly nor completely flat. Half marathon participants experience the longest course, with sights of Standley Lake, the Front Range, and the Flatirons in the distance. The race benefits Adaptive Adventures, provides virtual 10K and half marathon options, and is part of All-Out’s Endless Series, alongside Fallfest.

The Colorado Marathon is a road race in Fort Collins, typically held on the first weekend of May. It includes a full marathon, half marathon, 10K, 5K, and a children's run. The full marathon begins early, attracting thousands of participants, ranging from local residents running shorter distances to marathoners aiming for a personal best or a Boston Marathon qualification. The marathon route follows the Poudre River Canyon for most of its distance before entering Fort Collins' natural areas and concluding in the city. This predominantly downhill course is a significant draw; in its initial four years, 18% of participants achieved a Boston Marathon qualifying time. Originally named the Fort Collins Old Town Marathon, the event maintains a local focus through charity entries, which are priced higher with proceeds directed to local charitable organizations.

The Colorado 13er begins at the Home Depot on Dillon Road in Louisville, Colorado, offering a 13.1-mile half marathon, a 10k, and a 5k on the same race morning. The half marathon starts at 6:30 AM MDT, with the 10k and 5k following at 6:40 AM MDT. Runners aged 14 and older are eligible to participate. The half marathon follows a loop through Louisville, featuring views of the Flatirons. Nine miles of the course consist of flat, crushed gravel, positioning it between trail running and road racing, distinct from a pure pavement event. The 13.1-mile course includes 10 water station stops and 5 portable toilet stops. All race distances are mechanically measured. Half marathon finishers will receive a 13.1 medal, and approximately 30 percent of participants report this as their first race.