Ronkonkoma ( ron-KONG-kə-mə) is a hamlet and census-designated place (CDP) on Long Island in the Town of Islip, New York, United States. The population of the CDP was 19,082 at the 2010 census. The Ronkonkoma post office has the ZIP Code 11779, and serves parts of several hamlets and CDPs adjacent to Ronkonkoma.
Since 1988, Ronkonkoma has been the end of electrification along the Long Island Rail Road's Main Line. The track between Hicksville and Ronkonkoma has been referred to as the Ronkonkoma Branch. In 2017, Governor Andrew Cuomo announced the groundbreaking of a new $650 million development to create a Ronkonkoma Hub near the LIRR Line, similar to the hub in the neighboring Brookhaven.
Ronkonkoma was the terminus of the first road in the USA designed exclusively for automobiles, the Motor Parkway, constructed by a consortium of investors called the Long Island Motor Parkway, Inc., led by William Kissam Vanderbilt II.
Ronkonkoma is also home to Long Island MacArthur Airport (sometimes referred to simply as Islip Airport), airport code ISP, which is owned and operated by the Town of Islip. The New York Air Route Traffic Control Center is located in Ronkonkoma.
Ronkonkoma is located at 40°48′50″N 73°7′42″W (40.813962, −73.128438). According to the United States Census Bureau, the CDP has a total area of 8.1 square miles (21.1 km2), of which 7.8 square miles (20.3 km2) is land and 0.35 square miles (0.9 km2), or 4.07%, is water. The community is adjacent to Lake Ronkonkoma.