The Geist Race Series returns to Geist Reservoir on Saturday for its 18th year, and for the first time since 2008 the half marathon is sold out, the City of Fishers announced.

Spots remain in the 10K, 5K and a new 1-mile race. Runners can register online at GeistHalf.com until 6 p.m. Friday, Sept. 11, or in person until 8 p.m. Friday at packet pickup at Grace Church-Fishers, 12450 Olio Road.

The 1-mile run/walk is new this year and is aimed at families. All four races are open to walkers and to participants pushing jogging strollers, according to the city.

Gates open at 6 a.m. Saturday. Opening ceremonies begin at 7:20 a.m., with the half marathon, 10K and 5K starting at 7:30 a.m. The 1-mile race steps off at 9 a.m., and the event wraps up at 11:30 a.m.

The start and finish line sits at the north end of the Olio Road bridge over Geist Reservoir. The post-race party will take over Olio Road between 116th Street and 113th Street, and drivers should expect road closures in the area Saturday morning. The city has posted a closure map on its website.

Every participant receives a race shirt, a finisher medal and a ticket for one complimentary drink — alcoholic or non-alcoholic — at the post-race party. Vendors this year include MashCraft Brewing, Athletic Brewing, Java House, Pure Green, Eiffel Waffle Creamery and Ghost Mobile Kitchen.

The half marathon course, which loops runners across the reservoir, has long been the series’ signature event. A sellout after 17 years is a notable marker for a race that has weathered a crowded central Indiana running calendar.

More information is available at GeistHalf.com.