The light on Machias Seal Island, about 13 miles southwest of Grand Manan Island, New Brunswick, was lit for the first time in 1832. At one time there were twin lighthouses on Machias Seal, one tower near the western shore and a second, eastern tower about 30 feet from the present one. The first was pulled down in 1905 and the lumber used to build a small barn. After the present concrete tower was built in 1915, Don Daggett reduced the height of the eastern tower to keep the Island from being mistaken for a station with two towers. The keepers and their children referred to it as "the castle". It was used for a paint shed and, sometimes, for picking ducks.

A building on the northern point, used as living quarters by fishermen when they came ashore, was torn down in the early 1930s. During the 1940s, when Harvey Benson was principal keeper, with Lawrence Benson as his second keeper, there were eleven buildings on the Island.

John Conley was the first lightkeeper at Machias Seal Island, where he lived with his wife Elizabeth and their family. He died there ca. 1844 and his body was later removed to St. Andrews for burial. He and his son Obadiah were credited with saving the lives of the crews of at least seven shipwrecks.

The United States has long disputed Canadian ownership of Grand Manan Island even though the Passamaquoddy Islands Commissioners confirmed Canadian ownership in 1817 and Canada has exercised sovereignty over the island for 170 years. Because of this dispute, the light station is still manned, even though it has been automated for some time. The Department of Foreign Affairs pays the cost of maintaining keepers so that Canada can maintain its claim of sovereignty over the island. This makes it the only manned lighthouse remaining in the Maritime Provinces. Today there are four keepers, two taking rotating twenty-eight day shifts. There is also a Canadian Wildlife Service field station and bird sanctuary on the island, attracting tourists every summer.

Source: http://www.geocities.com/grandmanan.geo/sealisland.html - (web page of Deborah Daggett, widow of Douglas Daggett)