The island is a fragment of glacial terminal moraine approximately twelve miles off the coast of Rhode Island, of which it is part, and from which it is separated by BlockIslandSound.
Two historic lighthouses are present on the island;BlockIsland North Light, on the northern tip of the island (established in 1829, current lighthouse was built in 1868), and BlockIsland Southeast Light, is on the southeast side of the island (built in 1875).
BlockIsland's record high temperature is 95 °F. In comparison, Chester, Massachusetts which is far inland, has a record high of 107 °F. On the flipside, BlockIsland stays warmer than the mainland during the fall and winter months when the ocean remains relatively warmer than the mainland.