The Missouri River, a major tributary of the Mississippi, is often called the "Father of Waters."

The Missouri River, the longest river in North America, is famously known as the "Father of Waters" due to its immense length and historic significance. As a major tributary, it merges with the Mississippi River near St. Louis, greatly contributing to its flow and reach. This river played a crucial role in the exploration and settlement of the western U.S., supporting transportation, agriculture, and trade along its extensive course, which impacted multiple states.