New London Ledge Lighthouse is a lighthouse in Groton, Connecticut on the Thames River at the mouth of New London harbor.

New London Ledge Lighthouse was built in 1909 on the southwest ledge. It was originally called the Southwest Ledge light, but this caused confusion with Southwest Ledge Light in New Haven, Connecticut, so it was renamed New London Ledge Light in 1910. The light was automated in 1987.

New London Ledge is locally famous for the ghost of an early keeper named Ernie who allegedly haunts the lighthouse. The Coast Guard crew on duty at the lighthouse reported unexplained knocking, taking place at night.

Ledge Light has been featured on paranormal reality shows such as Scariest Places on Earth and Ghost Hunters.

Location: Thames River New London Harbor Connecticut United States Coordinates: 41°18'21.18"N 72°04'38.82"WCoordinates: 41°18'21.18"N 72°04'38.82"W Tower Constructed: 1909 Foundation: concrete pier Construction granite and brick building Automated: 1987 Height: 58 ft (18 m) Shape: short cylindrical tower on 3-story dwelling Markings: white tower, red lantern roof Power source: solar power Operator: New London Ledge Lighthouse Foundation Heritage National Register of Historic Places listed place. Light Focal height: 58 ft (18 m) Lens: Fourth order Fresnel lens (original), VRB-25 (current) Range: 15 nmi (28 km; 17 mi) Characteristic: three white flashes separated by 5 s, 10 s off, red flash, 10 s off