ST. LOUIS — Did you know that the Missouri River is about 100 miles longer than the Mississippi River? Google Search Trends showed people were looking up this fact Tuesday.

The Missouri River is the longest river in North America, stretching for 2,341 miles from its source in the Rocky Mountains of Montana to its confluence with the Mississippi River in St. Louis, Missouri. It is a major way for commercial and recreational boats to get to their destinations. It is also a major source of drinking water and farming water for the surrounding states. The river was an important resource for Native American tribes for thousands of years and played a crucial role in the expansion of the American West in the 19th century.

The Mississippi River is the second-longest river in North America, flowing for 2,350 miles from its source at Lake Itasca through the center of the United States to the Gulf of Mexico. The Missouri River is a tributary of the Mississippi River and is about 100 miles longer than the Mississippi River.

When compared to other world rivers, the Mississippi-Missouri River combination ranks fourth in length (3,710 miles), following the Nile (4,160 miles), the Amazon (4,000 miles), and the Yangtze (3,964 miles). When erosion and deposition happen at a river delta, the length may go up or down.