Chatham Lighthouse, known as Twin Lights prior to 1923, is a lighthouse in Chatham, Massachusetts, near the “elbow” of Cape Cod.
The station was established in 1808, the second light on Cape Cod. To distinguish it from Highland Light, the first Cape Cod light, and to act as a range, twin octagonal 40-foot (12 m) wooden towers were built. They were on skids so that they could be moved to keep them in line with the entrance channel as it shifted. Samuel Nye was appointed as the first Keeper of the Chatham Lights by President Jefferson on October 7, 1808.
- 1841 The wood octagons were replaced with 40-foot (12 m) brick towers
- 1857 Fourth order Fresnel lens installed
- 1879 Current structures, of brick lined cast iron, were built
- 1923 Northern tower of the pair was moved roughly 12 miles (19 km) north to become Nauset Light
- 1939 Chatham Light, which had been kerosene fueled since 1882, was electrified
- 1969 Fresnel lens was replaced with a Carlisle & Finch DCB-224 rotating light generating over 2.8 million candlepower
- 1969 Lantern replaced
- 1982 Automated.
Today, the former keeper’s house is an active U.S. Coast Guard station, and on-duty personnel living quarters. Search and Rescue, maritime law enforcement, and Homeland Security missions are carried out here. Flotilla 11-01 of the U.S. Coast Guard Auxiliary operates from this station.
Chatham Light was added to the National Register of Historic Places as Chatham Light Station on June 15, 1987, reference number 87001501.