Lost Lake

Photos

Overview

Lost Lake is the long northern basin of the Knops Pond/Lost Lake impoundment on Cow Pond Brook in Groton. MassWildlife explains that three ponds merged into one 204-acre water body when a dam raised the level, and the northern arm kept the name Lost Lake. It shares a boat ramp and fishery with Knops Pond.

Fishing

MassWildlife calls Knops Pond/Lost Lake an excellent seasonal trout pond and a good choice for bass and panfish. It's stocked with trout every spring and fall, and Cast The Water's MassWildlife records show a stocking on Oct. 9, 2026. Trout spread out in early spring, then gather in the deeper holes as the water warms. Bass hide in the abundant cover and vegetation, mostly in the upper and central basins.

Species

MassWildlife surveys found largemouth bass, chain pickerel, black crappie, yellow perch, bluegill, pumpkinseed, brown bullhead, yellow bullhead and golden shiner. Stocked trout are added in spring and fall.

Techniques

MassWildlife says bass anglers do best in early and late summer, early and late in the day, when boat traffic drops off. In winter, the abundant yellow perch are easy to jig in the shallow water.

Seasons

Trout are best in spring and fall, and bass in early and late summer. Ice fishing for perch is excellent.

Regulations

MassWildlife freshwater fishing regulations apply: https://www.mass.gov/freshwater-fishing-regulations. Confirm current seasons, limits and any special rules there; this page is not a legal source.

Licensing

Anglers 15 and older need a Massachusetts fishing license (MassWildlife).

Access

MassWildlife's Northeast District manages a concrete boat ramp on the northeast side of the impoundment, with parking for about ten vehicles. It suits small trailer boats, car-top boats and canoes. Contact the MassWildlife Northeast District, (978) 772-2145, about fees and restrictions.

Boat ramps & launches

MassWildlife concrete ramp (northeast side), which serves both Knops Pond and Lost Lake.

Activities

Fishing, boating, water skiing and swimming are all popular here (MassWildlife).

Ice fishing

MassWildlife calls this an excellent ice-fishing pond, with abundant yellow perch. Always check the ice yourself.

Water facts

Part of the Knops Pond/Lost Lake impoundment: 204 acres (MassWildlife), max depth just over 30 ft, average depth under 10 ft. Town: Groton.

Safety & advisories

The shoreline is about 70% developed, and the lake gets heavy recreational boat traffic in summer. Clean all boats and gear before moving between waters to stop aquatic hitchhikers (MassWildlife; see ProtectYourWaters.net).

Nearby waters

• Knops Pond · 0.9 km (MA)
• Duck Pond · 0.9 km (MA)
• Baddacook Pond · 2.7 km (MA)
• Long Pond · 3 km (MA)
• Spectacle Pond · 3.7 km (MA)
• Forge Pond · 3.7 km (MA)

More in Middlesex

• Squannacook River (MA)
• Baddacook Pond (MA)
• Knops Pond (MA)
• Nissitissit River (MA)
• Althea Lake (MA)
• Barkers Pond (MA)