Simon's Seat from Thruscross Reservoir
This route crosses two distinct landscapes in one loop - the flooded Washburn Valley around Thruscross, then the high gritstone fell of Simon's Seat - with barely any road between them.
Effort: Long day out, serious climb
Underfoot: Technical, navigation required
E4·T4 — how we grade routesNo photos of this route yet. Sign in to add one
Mostly on runnable ground, but most runners still walk the steepest climbs.
A long loop from Thruscross Reservoir in the Washburn Valley, crossing into Yorkshire Dales National Park to reach Simon's Seat at 479m before looping back. 28.7km, 828m of ascent, crossing grouse moor and open fell.
This route crosses two distinct landscapes in one loop - the flooded Washburn Valley around Thruscross, then the high gritstone fell of Simon's Seat - with barely any road between them.
The route
This loop starts at Thruscross Reservoir in Nidderdale, climbs out of the Washburn Valley, and crosses the boundary into Yorkshire Dales National Park to take in Simon's Seat before returning. At 28.7km with 828m of ascent, it's the longest and most demanding route in this set, and the distance is spread across genuinely varied ground rather than one repeated climb.
The reservoir start
Thruscross Reservoir was built in 1966, flooding the former village of West End - in dry spells, remnants of the old settlement can still be seen as the water level drops. The reservoir sits in the southern part of Nidderdale, and the Yorkshire Water car park here is the obvious place to start, though it's pay-and-display by card or RingGo, with no cash option.
Simon's Seat
Simon's Seat tops out at 485m, a prominent outcrop of millstone grit on the eastern side of Wharfedale, and reaching it means crossing Barden Fell - open access land managed by Bolton Abbey Estate as grouse moor. There's no public right of way directly to the summit, so the approach follows a permissive route via the Valley of Desolation, and in poor visibility this stretch needs proper map skills rather than guesswork. The ground here is peaty and can be genuinely boggy underfoot, particularly after rain.
Access and hazards
Grouse shooting runs from 12 August to 10 December, with no shooting on Sundays, and outside that window the moor is open. One rule applies regardless of season: dogs are not permitted on Barden Fell, so this isn't a route to bring one along for. Combined with the distance and the remoteness of the high section, this is a route to save for good visibility and a day when you're confident navigating without obvious paths to follow.
Why it works
What makes this loop worth the effort is the contrast - flooded valley, working grouse moor, and a genuine Dales summit with a name and a history, all in one continuous run. It's a route for runners who've done the shorter Wharfedale loops and want to step up to something that demands more from both legs and navigation.
Partner · affiliate policy
No public right of way to the summit - the approach via the Valley of Desolation needs map skills in poor visibility, and the ground is peaty and boggy underfoot in places. Grouse shooting runs 12 August to 10 December (no shooting Sundays), and dogs are not permitted on Barden Fell at any time of year.
Summits on this route
Safety on this route
- No signal? Text 999 — pre-register first: text register to 999
- Tell someone your route and expected return time before you head out
Leave No Trace
- Leave nothing but footprints, take nothing but memories.
- Please respect the countryside and all its inhabitants.
- Dogs on leads near livestock, and around ground-nesting birds from March to July.
- Gates as you find them — open or closed, leave it that way for the farmer and the next runner.
- Take it all home — wrappers, peel, tissue, the lot. It doesn't count as biodegradable if you can still see it.
- Stick to the path where the ground either side is wet, planted, or nesting habitat.
Common questions
- Most runners complete Simon's Seat from Thruscross Reservoir in 3 hours 50 minutes to 5 hours 10 minutes, depending on pace and conditions.
Run by us· last checked June 2026
Jason Millward has run this route and written it up from the ground. How we check routes
About the author
Runner reports
Nobody's logged a run here yet. If you get out on it, a few lines about how it went helps the next person plan their day.
Routes nearby
Start from a town: Ilkley 10.3 km
EASY
MODERATE
HARD
MODERATE
EASY
EASYRaces on this ground
All Nidderdale races →Races starting within 20 km of the Simon's Seat from Thruscross Reservoir start, nearest first. If you are entered for one, this route is the rehearsal.
7
Nov
2026
The Grim Reservoir Dogs
Swinsty & Fewston Reservoir car park, North Lane, near Otley · It's Grim Up North Running · 3 miles away
A run with your dog round Swinsty and Fewston reservoirs on good woodland trail, one 3.3-mile loop or two. A fun dog race, not run under canicross rules.
Entries open
£18–£29
7
Nov
2026
Swinsty & Fewston Lakeside Dash
Swinsty & Fewston Reservoir car park, North Lane, near Otley · It's Grim Up North Running · 3 miles away
The 6.7-mile loop of Swinsty and Fewston reservoirs on well-kept trail, run once, twice, three or four times for the half, the twenty and the marathon. Everything starts at nine.
Entries open
£29–£43
7
Nov
2026
Moonlight Meander
Swinsty & Fewston Reservoir car park, North Lane, near Otley · It's Grim Up North Running · 3 miles away
Swinsty and Fewston in the pitch dark: one or two laps of the 3.3-mile woodland loop by head torch, fairy lights and whatever else you bring.
Entries open
£17–£29
6
Oct
2026
Autumn Headtorch Half
Swinsty Reservoir, North Yorkshire · Punk Panther · 3 miles away
The autumn running of the reservoir night race.
MODERATE TO HARD
Not open yet