When Chatham Light was first built on Cape Cod in 1808, it was actually twin lighthouses, in an effort to distinguish the new beacon from nearby Highland Light. The first sentinels were 40 feet high and set 70 feet apart. They were built of wood, with a small dwelling for keepers.

Erosion and storms badly damaged the twin lights, eating away at the point on which they stood.  Nonetheless, they remained in service for 33 years, when it was determined that they were decayed and in such disrepair, they should be replaced.

In 1841, 40-foot brick towers, built further inland from the rapidly eroding cliff, replaced the wooden towers.  In 1857, the twins received fourth order Fresnel lenses, each showing a fixed white light.

Before an 1870 winter storm, Chatham Lights stood 228 feet from the edge of a 50-foot bluff.  The force broke through beaches and over the next seven years, erosion took the lighthouses within 48 feet of the cliff’s edge.  Within another two years, the south tower teetered 27 inches from falling and fishermen were placing bets on when it would happen.  On December 15, the south tower fell to the beach below, and fifteen months later, the keeper’s house and north tower suffered the same fate.

Fortunately, the lens had been removed two years earlier and placed in a third set of Chatham Lights.  These towers were built of iron plates lined with brick.

In 1923, the north light was moved to Nauset Beach to replace the Three Sisters.  This ended 115 years of twin Chatham lighthouses.

In 1939, the Coast Guard brought electricity to Chatham, which had been fueled by kerosene since 1882.  The Fourth Order Lens and lantern room were removed in 1969 and replaced with more powerful aero beacons producing a rotating 2.8 million candlepower light.  A larger lantern room was built to accommodate the new system.  In 1982, Chatham Light was automated and remains an active aid to navigation.

The old lantern room and Fresnel lens are on display on the grounds of the Chatham Historical Society.  The light is in operation whenever the museum is open.

Although erosion control efforts have slowed its progress, hurricanes and storms continue to threaten the old lighthouse.  Still owned and managed by the USCG, the Chatham Light is only open on special occasions and by arrangement with the Coast