Contoocook Beach is the Town of Jaffrey's swimming beach on Contoocook Lake, at 191 Squantum Road on the lake's north shore. Jaffrey has more than one swimmable water body, including Thorndike Pond to the north and Gilmore Pond to the east, but this is the one the town staffs and maintains as a public beach. The lake runs roughly 2.8 miles long and half a mile wide across 344 acres, straddling the Jaffrey and Rindge town line, and together with Pool Pond it forms the headwaters of the Contoocook River.

The swimming here is shallow and warm. Contoocook Lake averages about 7 feet deep and bottoms out near 23 feet, so the shallows heat up early in the season and stay comfortable into September. The beach is real sand, and the bottom stays sandy through the roped area before it softens into silt farther out. Entry is a walk-in wade down a gradual slope with no drop-off, which is why the beach fills up with families carrying small children. Buoyed swim lanes go in for Memorial Day weekend and come out after Labor Day.

Mount Monadnock sits about seven miles northwest, 3,165 feet and the highest ground in Cheshire County, and on a clear afternoon it holds the skyline across the water. The lake is a reservoir by history as much as by classification: a beaver dam held it back first, the Red Dam finished the job around 1860, and by 1872 it was a recreational lake with steamers and summer cottages. The level is still managed at the spillway and gets raised in early spring, so June water can sit higher and colder than late August water.

Facilities are better than most town beaches this size. There is a concession stand, a bathhouse with changing rooms and restrooms, a covered pavilion, picnic tables and a sand volleyball court. Lifeguards work posted hours; outside those hours it is swim at your own risk. The grounds and the lot are open 8am to dusk daily. A public boat access sits at the same Squantum Road address, and the Monadnock Recreational Rail Trail crosses the west arm of the lake on a causeway a mile or so away, a flat easy walk or ride. The lake is a warmwater fishery for largemouth and smallmouth bass, perch, black crappie, bluegill and chain pickerel, though fishing has to stay outside the roped swim area.

The access rules are what catch visitors out. The beach itself is open to residents and non-residents alike and there is no admission fee to swim. The parking lot is the catch: it is restricted to vehicles displaying a Jaffrey Transfer Station Permit, which only town residents can get from the Town Clerk, and an unpermitted car parked there draws a $50 fine and can be towed. Non-residents park free at Humiston Field, 31 Howard Hill Road, and walk over, so build that walk into the plan rather than circling the lot.

Other posted rules: no dogs on the sand or in the water, no flotation devices except during supervised swim lessons, no snorkels or fins although masks and goggles are fine, no glass anywhere on the grounds, no alcohol, and no fires or grills on the beach.

Contoocook Lake has had cyanobacteria blooms reported in past summers, and New Hampshire DES posts in-season advisories on its Healthy Swimming Mapper. The Contoocook Lake Area Preservation Association monitors clarity and nutrients alongside the state, and its 2025 conductivity and chloride readings were the best the group had recorded since 2012. Check the mapper the morning you drive out.