 Running from the equivalent of East 46th to 85th Streets on Manhattan Island, it is about long, with a maximum width of , and a total area of .Together with Mill Rock, Roosevelt Island constitutes Manhattan's Census Tract 238, which has a land area of , and had a population of 9,520 as of the 2000 United States Census.It had a population of 11,661 as of the 2010 United States Census.