Mississippi's governor declared a state of emergency Saturday as the Pearl River continued to rise, and flooding hit Jackson, the state capital.
Republican Gov. Tate Reeves urged residents in low-lying areas to evacuate as the swollen river continued to rise.
The Pearl River was expected to hit 38 feet late Saturday night or early Sunday, the highest level it has reached in decades.
The flooding is expected to extend beyond the northern areas of the capital and potentially lap at some buildings downtown, according to the National Weather Service.
River said: "We do not expect this situation to improve in the near future."