It happened just before 1 a.m. near Bowmanstown, Pennsylvania.
Crews used boats to save four people from a raft and two others on land.
They say two other people fled from the scene.
Experts had warned prior to the holiday weekend that the Lehigh River was four times higher than normal this time of year. The water temperature is also very cold.
Pennsylvania state police say the people rescued could face charges due to the danger they created.