DateExpected
Late October 2026
Based on past editions. We'll confirm when the organiser announces.
Venue
Philipstown Recreation Department, 107 Glenclyffe Drive, Garrison, NY 10524
Garrison, Putnam County
Countdown
October
A proper trail half with 621 m of climbing, so expect some work, but the field is small and the welcome is for runners and fast hikers alike.
Key facts
01Cut-off is 13:00, four hours after the gun
02One aid station, passed twice (at miles 5.5 and 8)
03Open to runners or fast hikers, no formal entry restriction
Create a free training plan for the Castle to River Run 21 km
7-day free trial, no card required
The course
The route
Garrison
Distance21km
Total climb621m
StartElevation
0 kmDrag map to rotate20.9 km
Weather
Late-October, Garrison
16°CTypical high
5°CTypical low
-6°CColdest in 20 years
32%Days with rain
Highs around 16°C and lows around 5°C, but it has dropped to -6°C. Rain on 32% of days. Pack for the cold end, not the average.
NASA POWER data, 2006-2025, the week either side of race day
2025 results
Who finishes, and how
#RiderTimeAvg speed
01Mackenzie Allison01:57:3610.8 km/h
02Catherine Huang01:59:4810.6 km/h
03Victoria Moss02:14:519.4 km/h
27
Women finishers
2:32:30
Median time
8.3 km/h
Median speed
Women · 2025 results, as published by the organiser.
How fast could you finish?
Get a prediction based on your recent training
Organiser
Training
Training for the Castle to River Run 21 km
We don't do generic plans. We combine deep knowledge of this race's demands with your recent training, then build a plan with you that progresses as you do.
Beina integrates directly with your existing tools to understand your current fitness, and synchronise your planned sessions.
Intervals.icuWhat a Castle to River Run 21 km plan targets
Typical sessions
21 km with 621 m of climbing
Time on feet and fatigue resistance
Fuelling and pacing for the whole event
What your weeks look like
Typical sessions
Long runs that build time on your feet
Tempo and threshold sessions to hold race pace
Back-to-back weekend runs for fatigue resistance
Not a generic schedule
Typical sessions
Built from your current fitness and the time you actually have
Adapts every week as Beina learns how you respond
Syncs your sessions straight to Garmin and Wahoo
One clear next session, never a wall of spreadsheet
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Get your Castle to River Run 21 km plan.
7-day free trial, no card required.
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