St. James is a hamlet and census-designated place (CDP) in Suffolk County, New York, United States.

St. James is part of the Town of Smithtown and is located on the North Shore of Long Island.

In the early 20th century, St. James was a popular vacation spot for glitterati of the stage and screen.

Summer residents included Lionel, Ethel, and John Barrymore, Buster Keaton, Myrna Loy, and Irving Berlin, among others.

[2][3] Noteworthy persons of the hamlet have included Stanford White, architect; William Jay Gaynor, New York State Supreme Court Justice and Mayor of New York City; Wilton Decker, Inventor of the electronic piano; Mick Foley, professional wrestler; Soledad O'Brien, television personality; John Miceli, drummer for Meat Loaf; and John Petrucci, lead guitar player for Dream Theater.

[5] According to the United States Census Bureau, the CDP has a total area of 4.5 square miles (12 km2), all land.

This allows for quick access to the Bridgeport & Port Jefferson Ferry, which offers transportation across the Long Island Sound to New England while avoiding New York City traffic.