Clarence DeMar Marathon: Pacing & Race-Day Strategy
Named for the seven-time Boston champ, a net-downhill point-to-point built for BQ attempts.
Last updated
- Where:
- Gilsum to Keene, New Hampshire
- When:
- Sunday, September 27, 2026
- Course:
- Net downhill · point-to-point
- Best run as:
- Even pace
Course & elevation
The Clarence DeMar honors the seven-time Boston Marathon winner with a fitting net-downhill point-to-point from Gilsum to Keene. The course sheds a few hundred feet through quiet New Hampshire countryside and rail-trail, with a gentle, steady descent rather than any steep plunge. A handful of small rises interrupt the drop, but the overall tilt makes it a favorite for runners chasing a Boston qualifier.
- Start → Finish
- 620 → 355 ft
- Net
- −265 ft
- Total gain
- ≈ 265 ft
The certified route
Point to point from Gilsum to Keene, heading south through Surry with a turnaround at the Surry Dam, then through Keene to the finish at Keene State College.
- Start
- On the west side of Alstead Hill Rd in Gilsum, 30.1 m south of the guardrail on the east side of the road and 35.6 m north of driveway 30.
- Finish
- On Appian Way, 102.4 m west of Main St, marked with a cement pillar in front of the Mason Library at Keene State College.
Underfoot
Fully paved.
Through, in order
Gilsum · Surry · Keene
What you pass
- Mile 11: the turnaround on the Surry Dam
- Mile 19: Wheelock Park
- Mile 22: through the cemetery
Worth knowing
- Lane restrictions are written into the certification: runners keep left on Rt 12A, Surry Dam Rd, Court St, Arch St, and Optical Ave, and keep right on Maple Ave, Summit Rd, and Hastings (until 10 Hastings).
Transcribed from the USATF certificate for Clarence DeMar Marathon (NH25006JK), measured 23 July 2025. Where the certificate is silent, so are we.
Key moments
- Mile 1–5Gentle early descent through Gilsum; relax and let the grade set an easy rhythm.
- Mile 8–20Steadily dropping countryside and rail-trail miles; lock into goal pace.
- Mile 24–26.2A few small rises before the finish in Keene. Stay strong over the last bumps.
Pacing strategy
Run even effort and the steady downhill will hand you a slightly negative split without forcing it. Keep your stride light on the descent to protect your quads, and don’t let the small late rises break your rhythm.
Pacing by goal time
Checkpoint splits for four common goals at Clarence DeMar Marathon. These are effort-even rather than pace-even: the paces shift with the course profile, so climbs are slower and descents faster by the amount the grade actually costs. For any other goal time, use the planner below.
| Checkpoint | Sub-3:00 | Sub-3:30 | Sub-4:00 | Sub-4:30 |
|---|---|---|---|---|
| Mile 3.1 | 20:306:50/mi | 23:557:58/mi | 27:209:07/mi | 30:4510:15/mi |
| Mile 6.2 | 41:046:52/mi | 47:548:01/mi | 54:459:09/mi | 1:01:3510:18/mi |
| Mile 9.3 | 1:01:376:52/mi | 1:11:548:01/mi | 1:22:109:09/mi | 1:32:2610:18/mi |
| Mile 12.4 | 1:22:116:51/mi | 1:35:537:59/mi | 1:49:359:08/mi | 2:03:1710:16/mi |
| Mile 15.5 | 1:42:496:52/mi | 1:59:588:01/mi | 2:17:069:09/mi | 2:34:1410:18/mi |
| Mile 18.6 | 2:03:276:53/mi | 2:24:028:02/mi | 2:44:369:11/mi | 3:05:1110:20/mi |
| Mile 21.7 | 2:24:046:53/mi | 2:48:058:02/mi | 3:12:069:10/mi | 3:36:0710:19/mi |
| Mile 24.9 | 2:44:446:53/mi | 3:12:118:02/mi | 3:39:389:11/mi | 4:07:0510:20/mi |
| Finish | 2:58:306:53/mi | 3:28:158:02/mi | 3:58:009:11/mi | 4:27:4410:20/mi |
Splits assume even effort and are adjusted for this course's climbs and descents, which cost more than they give back. A model, not a promise: wind and heat move real splits around. See how the pacing model works.
Plan your mile splits
Turn your goal time into a mile-by-mile plan for Clarence DeMar Marathon, built from this course's elevation. The even pace approach comes pre-selected, and grade-adjusted pacing evens out your effort across the climbs and descents.
Plan Clarence DeMar Marathon splitsFueling & hydration
Aid stations appear roughly every two miles, but the rural and rail-trail stretches reward carrying your own gels. Take a gel every 30–40 minutes on a fixed schedule so the quiet, fast miles don’t tempt you to coast through one.
Weather
Late-September in southern New Hampshire is usually cool and crisp at the start, close to ideal racing conditions for a hard effort.
What race morning has actually been like
The last 5 editions of Clarence DeMar Marathon, measured at the start line rather than averaged across the month. Starts have run 45–58°F, averaging 53°F.
| Year | Date | Start | Dew pt | Wind | By late morning |
|---|---|---|---|---|---|
| 2021 | Sep 26 | 53°F | 53°F | 6 mph | 64°F |
| 2022 | Sep 25 | 45°F | 48°F | 5 mph | 59°F |
| 2023 | Sep 24 | 53°F | 48°F | 6 mph | 58°F |
| 2024 | Sep 29 | 53°F | 53°F | 3 mph | 63°F |
| 2025 | Sep 28 | 58°F | 61°F | 6 mph | 72°F |
Dew point has reached 61°F (2025). Above about 60°F, sweat stops evaporating efficiently and most runners lose pace no matter what the thermometer says. It is the number to watch here, not the air temperature.
Dates derived from the race's published pattern (Last Sunday in September), observations at Gilsum, NH (start). Source: Open-Meteo historical reanalysis (ERA5), 7-11am local at the start line. Reanalysis is modelled from station observations, so treat it as a close record rather than an official one. See how race-morning weather is built.
Is Clarence DeMar Marathon a good Boston qualifier?
Yes. The course drops 265 ft net, comfortably inside the 1,500 ft threshold where Boston's downhill adjustment begins, so a time here is submitted as run.
This drop is our estimate rather than a figure from the course's certificate. If it sits near a threshold, confirm with the organizer.
Compare every course, how the downhill bands work, or work out your own target.
Dial in your pacing & fueling
New to how training builds toward a race like this? Start with Anatomy of a Running Plan, find your zones with the pace calculator, and plan race-day nutrition with the fueling calculator.
Related marathon guides
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- Sugarloaf MarathonCarrabassett Valley, Maine · May 16, 2027In neighboring Maine
- Avenue of the Giants MarathonHumboldt Redwoods, California · May 2, 2027Another flat course
- 26.2 with DONNAJacksonville Beach, Florida · Feb 7, 2027Another flat course
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