| September |
| Sep 30 | 25th Annual Black Bear Triathlon | Orono |
| Sep 30 | Gorham Savings Bank Maine Marathon/Relay/Half Marathon | Portland |
| Sep 29 | Eliot Festival Days 5k | Eliot |
| Sep 29 | Hyde Academy Cross Country Meet | Bath |
| Sep 29 | MS Brewer 5K | Brewer |
| Sep 29 | Monmouth Cumston Hall Applefest 5k | Monmouth |
| Sep 29 | Big Brothers Big Sisters Kids Maine Marathon Mile | Portland |
| Sep 29 | 5th Annual Hugs From Hayley 5K | Saco |
| Sep 29 | Rachel’s Run | Augusta |
| Sep 29 | Karen’s Energy 4 Life Cancer Run/Walk | Rockland |
| Sep 29 | Riverfest Jr Black Bear 5K and Fun Run Results for 5K | Old Town |
| Sep 28 | WMC Boys & Girls HS XC Meet Poland HS | Minot |
| Sep 26 | Coastal Running League Cross Country Meet | Falmouth |
| Sep 23 | 2nd Annual MAINEiacs Charities Half Marathon & 10K | Bangor |
| Sep 23 | Kittery PTA Seaside 4 Miler | Kittery Point |
| Sep 23 | 2012 Common Ground Country Fair 5K | Unity |
| Sep 22 | 12th Annual Ogunquit Beach Lobster Dash 5M | Ogunquit |
| Sep 22 | Gould Academy Cross Country Meet | Bethel |
| Sep 22 | Be a Friend in Action 5k | Ellsworth |
| Sep 22 | Combat Cancer 10K & 5K | New Gloucester |
| Sep 22 | Harvest Daze 5K | Sanford |
| Sep 21 | Falmouth High School Cross Country Meet | Falmouth |
| Sep 21 | KVAC Boys & Girls XC @ Cony HS | Augusta |
| Sep 21 | Lincoln Academy Cross Country Meet | New Castle |
| Sep 20 | Bond Brook 5k Trail Race Series | Augusta |
| Sep 16 | 14th Annual Womens Fitness Studio & Spa 5K | Brunswick |
| Sep 16 | Bob Boucher Memorial 5K | Auburn |
| Sep 16 | Komen Race for the Cure | Bangor |
| Sep 16 | Portland Trails Trail to Ale 10K | Portland |
| Sep 15 | 8th Annual Mount Desert Island YMCA Fall 5K | Bar Harbor |
| Sep 15 | Bar Harbor Bank & Trust Half Marathon and Early Bird Walk | Bar Harbor |
| Sep 15 | Bowdoinham 5K Chicken Run and 1 Mile Fun Run | Bowdoinham |
| Sep 15 | Karo-5K | Portland |
| Sep 15 | Pathway Vineyard 5K | Lewiston |
| Sep 15 | Run for the Hills 10K | Belfast |
| Sep 15 | Strive for 5 | South Portland |
| Sep 15 | Mustang 5k | Waterboro |
| Sep 14 | KVAC: Lin Ac, EL, Law, Cam Hills, Ersk, Belf, Oceanside@Medomak | Waldoboro |
| Sep 13 | Bond Brook Trail Race Series (updated 9/13/2012) | Augusta |
| Sep 9 | Dan Cardillo Memorial 5K | Falmouth |
| Sep 9 | 911 Memorial 5K Run/Walk | Gorham |
| Sep 9 | Dancing Trees Annual “winter warmth” 5K Road Race | Oxford |
| Sep 9 | Komen Race for the Cure Portland | Portland |
| Sep 9 | Lake Auburn Half Marathon and 5k (updated 9/9/2012) | Auburn |
| Sep 9 | Bradbury Bruiser – 12 Mile Trail Race | Pownal |
| Sep 9 | Pumpkinman Half Iron Triathlon and Aquabike | South Berwick |
| Sep 8 | Hot Pursuit 5K | Brunswick |
| Sep 8 | Run for the Trees In Memory of Nate MacConnell | Augsusta |
| Sep 8 | 7th Annual Suddy 5K Run | Eastport |
| Sep 8 | Saco Bay PT 5K Cure for Breast Cancer | Saco |
| Sep 8 | Hill N the Ville | Waterville |
| Sep 8 | Pumpkinman Sprint Triathlon | South Berwick |
| Sep 7 | Greely High School Cross Country Meet | Cumberland |
| Sep 7 | WMC: Falmouth, Merriconeag @ GNG 2012 | Gray |
| Sep 5 | Weekly Back Cove 5K | Portland |
| Sep 3 | 50th Annual Bangor Labor Day Road Race | Bangor |
| Sep 2 | Labor Day Classic 5K | Biddeford |
| Sep 2 | Eastport Salmon Festival 5K | Easport |
| Sep 2 | Furry Friends 5K | Portland |
| Sep 2 | Maine Sport Triathlon | Camden |
| Sep 1 | Race to the Lakes 5K | Belegrade |
| Sep 1 | Maine Maritime Academy Opening Weekend 5K | Castine |