How far up stream does salt water go up the Mississippi river?

Saltwater intrusion in the Mississippi River can extend up to 100 miles or more during periods of low river flow, particularly in the lower river basin near New Orleans. Factors such as tidal influences, seasonal variations, and upstream water management practices can affect the extent of this intrusion. Typically, it is most pronounced during drought conditions or when the river's flow is reduced. The precise distance can vary based on environmental conditions and human activity.