High Quality Content by WIKIPEDIA articles! Lake Ronkonkoma, Long Island`s largest freshwater lake, is in Suffolk County, New York, and has a circumference of about 2 miles (3.2 km), and is 0.65 miles (1.05 km) across on average. A kettle lake formed by retreating glaciers, it is owned by the Town of Islip under the terms of the Nichols Patent, the land around it is controlled by three town governments - Smithtown, Islip and Brookhaven. The separation originated because three different Indian communities claimed lands on differrent shores, and these claims continued when the tribes gave separate deeds to the land under their control. The name Ronkonkoma comes from an Algonquian expression meaning "boundary fishing-lake", also earlier written as Raconkumake and Raconkamuck.