Half Marathon races near San Anselmo

The Reservoir Dogs Trail Run is an October trail race held at San Pablo Reservoir, located near Orinda in the East Bay. All race distances commence and conclude at the San Pablo Reservoir Visitor Center. Participants can select from 5K, 10K, half marathon, or 35K distances. The event has a participant cap of approximately 300 individuals across all races. Inside Trail Racing organizes this event. The longer distances feature a 6.5-hour time limit, maintaining the structure of a genuine trail race as opposed to a casual reservoir run. The course's distinctive feature is its complete circuit around Briones Reservoir using EBMUD trails, incorporating segments typically accessible only with permits. Expect a mix of moderately technical dirt paths, open fire roads, undulating hills, wooded single-track, winding single and double-track sections, exposed ridgelines, and expansive vistas of the watershed. The 10K, half marathon, and 35K races involve less elevation gain compared to many other Inside Trail events, allowing for faster times while still providing road runners with a true trail challenge. Aid stations are equipped with gels, trail mix, salty snacks, fruit, Coke, and Stroopwafels; however, participants must carry their own water between stations. Finishers receive a tech shirt and a medal, age-group victors are awarded trophies, and one participant receives the unique "Dead Last Finisher" award. Notably, dogs are prohibited despite the race's name.

The Halloween Trick or Trot Run is a Halloween road race held at Crissy Field in San Francisco. Participants can select a 1 Mile, 5K, 10K, or half marathon, accommodating those seeking a brief, enjoyable run and those targeting 13.1 miles. The race takes place in San Francisco County, within the Bay Area. The start is located at Crissy Field, and the course map is emailed to participants. The Halloween theme is integral to the event; participants are encouraged to bring a friend, set a goal, and receive free Halloween candy post-run.

The PB&J Fuel Run 5K/10K/13.1 SAN FRANCISCO is a running event in San Francisco offering 5K, 10K, and half marathon distances. Organized by The Best Races, its peanut butter and jelly theme lends a playful tone rather than intense race-day focus. The event features a relaxed atmosphere. Participants are encouraged to "spread the fun" and approach the day with "no stress, no expectations," running at their own pace. While specific route details are not provided, the race emphasizes feel-good miles, a satisfying finish, and the concept of running your own way.

The Golden Gate Half Marathon & 5K is a Sunday race in San Francisco with the bridge at the center of the day. Runners choose between a half marathon and a 5K, with the shorter distance open to both runners and walkers and aimed at a wide range of abilities. The half marathon crosses the Golden Gate Bridge twice, giving runners long looks at the bay, Alcatraz, and San Francisco from one of the city’s most famous landmarks. The event draws runners from around the world, uses the hashtag #RunTheBridge, and is tied to the Bay Area running community as much as to the bridge itself.

The Veterans Day Freedom Run in San Francisco is a road run at Crissy Field, offering 5K, 10K, and half-marathon distances. It is centered on Veterans Day gratitude, allowing participants to run or walk without the pressure of a competitive race. Waves are capped and may sell out; a waitlist and virtual option are available when in-person spots are full. The event accommodates all paces and ages, with participants under 18 requiring a guardian. Timing is optional; runners may use an app to track and submit results online, or seek assistance from coordinators, as there are no timing chips. Participants can fundraise for a chosen charity, with all net proceeds directed to that cause. Included with registration are a running shirt for U.S. participants, a finisher medal, a towel or giveaway item, a digital training pack, online results, a completion certificate, and an invitation to local running clubs.

Jingle All the Way: A Merry Christmas Run is a holiday race series in San Francisco offering 5K, 10K, and half-marathon distances. A Family 1 Mile Fun Run is also available for those not wanting to commit to longer distances, and a virtual run option exists for remote participation. The event is scheduled before Christmas celebrations, encouraging families and friends to gather. The theme focuses on Christmas values like spreading love, selfless giving, and enjoying time with others. The 5K, 10K, and half-marathon registrations include an eco-registration option for participants who prefer not to receive a shirt.

The Golden Gate Trail Run is a winter trail race in San Francisco offering distances for various runners, from an 8K and half marathon to marathon, 50K, and longer ultra options in the Spartan Trail version. A free 50-yard dash for children aged six and under is also available, showing the event caters to more than just ultrarunners. The running surface is soft trail, the route is hilly, and typical conditions are mild, around 64°F. The course takes runners across the Golden Gate Bridge and into the Marin Headlands, with views over the Pacific Coast, Tiburon, San Francisco, and the bridge. The average altitude is low at about 426 feet, but the Headlands provide significant climbing and exposed coastal trail running, distinct from a flat city route. Volunteers can earn credits toward other U.S. Spartan events, and published results are available for several recent editions.

Bay Breeze begins and ends at San Leandro Marina Park, offering half marathon, 10K, and 5K races on Valentine’s Weekend. This Brazen Racing event, situated on the east side of San Francisco Bay, features a mostly flat bayside trail adjacent to the water. The course suits runners aiming for a fast time, and it welcomes walkers at all distances, including a dedicated Hiker Division. The course traces the shoreline near the marina, providing open views of the bay toward San Francisco and long sections with the water close by. Organizers describe it as a "breeze" relative to Brazen’s steeper Bay Area races, aligning the name with its character. The event has been held for over ten years, attracting more than a thousand finishers across its distances, and has returned to San Leandro Marina Park after previous editions were held in Fremont.

Victory begins at the historic Craneway Pavilion in Richmond, California, sending runners onto the Richmond Bay Trail along San Francisco Bay. The series includes a half marathon, 10k, and 5k, allowing participants to select anything from a short bayfront run to a longer, flat road course. The courses are flat and fast, suitable for beginners and those aiming for a personal record. The route follows the San Francisco Bay Trail, offering open views across the bay toward the Golden Gate Bridge, the Bay Bridge, and Mt. Tamalpais. The race name references Richmond’s World War II home front history, when hundreds of ships, including Victory ships, were built in the area, and the nearby Ford assembly plant shifted from car production to military vehicles. Runners can also combine this with the Breeze to Victory race for the B2V Double, receiving a combined “mega medal” with a special middle piece for completing both events.

The Montara Mountain Trail Run is a February trail-running series held in San Pedro Valley Park, Pacifica, California. The main races begin in the morning, offering runners a selection of distances: 10K, half marathon, 20.7 miles, marathon, and 50K. A free 50-yard dash is available for children aged six and under, alongside a free Coastal Testing event that starts before the main races. The course ascends Montara Mountain, an area noted by the race organizers as the sole undisturbed coastal mountain habitat along over 100 miles of coastline. Participants will run past huckleberry, honeysuckle, lilac, chinquapin, and manzanita groves, with views of the Pacific Coast appearing as they climb. The event likely attracts a diverse field because of the range of distances from a short trail race to an ultramarathon, and the kids' dash encourages families to attend before the longer races commence.