Both towers are identical and were completed in 1861. They are each 124 feet high and stand about 164 feet above the waterline. They are constructed of solid granite on the outside and a two foot thick inner wall of brick.Each block of granite weighs over 10 tons.
Each tower is 22 feet in diameter at the base and 13 feet at the lantern room. There are 156 steps to the top.
From the tower one is able to see the skyline of Boston to the South and the mountains of Maine to the North-west. Looking down to the southeast about half mile off shore you may see an iron pole jutting out from the water. This marks an area called the “Londoner” so named because of the reef just below the surface which has claimed hundreds of vessels most bound to Boston from London in the early 1700’s. This reef was one of the reasons the original twin towers were built by the British of Massachusetts Bay Colony in 1771. The other was to be able to differentiate Cape Ann Light Station from Boston Light to the south and Portsmouth Light to the north.