| 4366 | 10 Oct 26 | OKLAHOMA CITY TRAIL RUNNING FESTIVAL | ['3M'/ '9M'/ '21M'/ '31M'/ 'Ultra'] | Oklahoma City, OK |
| 4367 | 13 Mar 27 | Okie Half | 5K/13.1M | Muskogee, OK |
| 4368 | 26 Nov 26 | Ojai Family Fund Turkey Trot | 3M | Ojai, CA |
| 4369 | 14 Nov 26 | Oilman Texas Triathlon | 5K | Conroe, TX |
| 4370 | 15 May 27 | Oil Creek 5 and 13 Stacked Trail Races | 5M/13M | Titusville, PA |
| 4371 | 10 Oct 26 | Oil Creek 100 Trail Runs | 25K/50K/100K | Titusville, PA |
| 4372 | 26 Sep 26 | OHS Paws in the Park 5K | 5K | Seneca, SC |
| 4373 | 01 Jan 27 | OhioHealth First On The First 5K | 5K | Westerville, OH |
| 4374 | 26 Sep 26 | OhioGuidestone Promise Run | 1M/5K/10K | Berea, OH |
| 4375 | 03 Oct 26 | Ohio Swiss Festival Cheese Chase | 1M/5K/10K | Sugarcreek, OH |
| 4376 | 19 Sep 26 | Ohio Fall Challenge | Olympic/Sprint/supersprint duathlon/supersprint triathlon | Mount Sterling, OH |
| 4377 | 25 Oct 26 | Ohio Cross Country Middle and Elementary State Championships | 2M | Dublin, OH |
| 4378 | 19 Sep 26 | Ohio Brewery Running Series | 5K | Bowling Green, OH |
| 4379 | 03 Apr 27 | Ohio and Erie Canal Reservation parkrun | 5K | Cleveland, OH |
| 4380 | 07 Nov 26 | Ohio (Cleveland Area) SCADaddle 5K | 5K | Macedonia, OH |