The Port Jefferson Harbor is on the waterways listed below.
|Long Island Sound||New York Harbor River System|
While many waterways are not part of a larger waterway system, there are a some that belong to two waterway systems. For example, the Tennessee River is a natural river tributary in the Mississippi River System while also being connected to the Mobile Bay River System via the Tennessee-Tombigbee Waterway.
|Maps of United States: small large|