Explore Arnold
Lyons Reservoir
A small, quiet reservoir in the pines above Twain Harte — shore fishing, a paddle on flat water, and a shoreline that stays green when the foothills have burned brown. About an hour and a quarter from the cabins.
First things first
First things first
Lyons sits at about 4,200 feet on the South Fork Stanislaus, a few miles off Highway 108 above Twain Harte. It is a water-supply reservoir rather than a recreation lake, which shapes everything about it: modest facilities, a low speed limit, and a calm that the bigger lakes lose by July.
From Arnold it is about an hour and a quarter by way of Sonora. It suits a morning rather than a whole day — fish, paddle, eat a sandwich on a rock — often combined with lunch in Twain Harte on the way home.
Geography
Where Lyons Reservoir sits
Lyons is a water-supply reservoir on the South Fork Stanislaus, part of a system first built in the nineteenth century to serve the Gold Rush towns downhill.
It is small, calm and shaded, with modest facilities and rules that reflect its role as drinking water rather than recreation.
It is about 45 miles from Chalet Bruin and Koda Loft via Sonora — roughly an hour and a quarter.
- Region
- Western Sierra Nevada, upper foothills
- County
- Tuolumne County
- Elevation
- About 4,200 ft
- Nearest town
- Twain Harte, about ten minutes below
- Getting there
- Highway 108 to Twain Harte, then the Lyons Reservoir road
Fishing and paddling
The reservoir is stocked with rainbow trout and holds browns and some warm-water fish in the shallows. It fishes well from the bank in spring and autumn, and from a small boat, kayak or paddleboard through the summer. A California fishing licence is required for anyone sixteen or older.
Non-motorised and small electric craft suit the water best; check the current rules with the operator and the Forest Service before arriving with anything larger, because access and boating restrictions on water-supply reservoirs change without much fanfare.
The dam, the flume and a bit of history
The reservoir is part of a nineteenth-century water system built to serve the Gold Rush towns below, and the old ditch and flume alignments still run through the woods nearby. It is a modest, human-scaled piece of engineering next to the big Sierra dams — a wall, a spillway and a lot of quiet water.
Swimming is generally discouraged or prohibited on drinking-water reservoirs, and the rules here are posted on site. Read them when you arrive rather than assuming, and go to the Stanislaus River or Pinecrest if swimming is the point of the day.
Season and access
Spring and autumn are the best times: mild air, cool water and active fish. Summer is pleasant early and hot by midday, and at this elevation winter brings occasional snow that can make the access road briefly awkward but rarely closes it for long.
Facilities are limited to a small parking area and a launch spot. There are no shops; Twain Harte, ten minutes away, has a market and somewhere to eat.
Where to stay for a Lyons morning
This is a stop rather than a destination, and it slots neatly into a stay based in Arnold — an hour and a quarter each way, with Twain Harte, Sonora and Columbia all on the same loop.
Good to know
Frequently asked questions
Can you swim at Lyons Reservoir?+
Swimming is generally restricted on drinking-water reservoirs and the rules are posted on site. For a swim, head to Pinecrest Lake or the Stanislaus River instead.
What fish are in Lyons Reservoir?+
Mainly stocked rainbow trout, with browns and some warm-water species in the shallows. A California fishing licence is required from age sixteen.
Can you take a boat?+
Small non-motorised and electric craft suit the reservoir. Boating and access rules on water-supply reservoirs change, so check current restrictions before you drive up with anything larger.
How far is it from Arnold?+
About an hour and a quarter via Sonora and Highway 108, ten minutes above Twain Harte.