The fire broke out in the swamp grass along the north shores of the Raritan River. It spread quickly with the help of 10- to 15-mile per hour winds.
About 250 acres have burned, and the smoke could be seen for miles for most of Thursday. Nobody was injured and no buildings were damaged.
The New Jersey Department of Environmental Protection reported that there are still small areas that continue to burn so it's not out yet. Crews will let it burn itself out.
Firefighters let the flames burn in the grassy area. The fire was threatening some railroad tracks. Air support was brought in to keep the flames from spreading to nearby businesses.
No injuries have been reported and no evacuations were ordered.