The Great Flood of 1844 is the biggest flood ever recorded on the Missouri River and Upper Mississippi River in North America in terms of discharge. The adjusted economic impact was not as great as subsequent floods because of the small population in the region at the time. The flood devastation was particularly widespread since the region had few levees at the time, so the waters were able to spread far from the normal banks. Among the hardest hit in terms of mortality were the Wyandot Indians, who lost 100 people in the diseases that occurred after the flood in the vicinity of today's Kansas City, Kansas.

The flood formed a large sandbar in front of the Wayne City Landing at Independence, Missouri, causing settlers to go further west to Westport Landing in Kansas City, which resulted in significant local economic and cultural impact.^[1] Independence had been the trailhead for several key emigrant trails, prior to 1846, both the Santa Fe Trail and one alternative eastern starting branch of the Oregon Trail. After the Mexican–American War treaty of 1848, the Oregon Trail's trailhead became a trailhead of the California Trail and an alternative beginning for the Mormon Trail.

In 1850, the United States Congress passed the Swamp Land Act providing land grants to build stronger levees.

The flood is the highest recorded for the Mississippi River at St. Louis. The discharge was 1,300,000 cubic feet per second (37,000 m³/s) in 1844, while 782,000 cu ft/s (22,100 m³/s) in 1951 and 1,030,000 cu ft/s (29,000 m³/s) in 1993.

Comparison to other big floods in Kansas City

Over time, channeling and levee construction have altered how floods affect various areas along the Missouri River. For example, here is a comparison of flood data at – and associated impacts on – Kansas City for three big floods since the early 19th century.

• Flood of 1851 — While the Great Flood of 1851 was most severe in Iowa, it also affected the Missouri and Mississippi river basins. In St. Louis, Missouri, on June 11, 1851, floodwaters rose to within 5 feet (1.5 m) of the 1844 flood, while at Cape Girardeau, Missouri, the flooding was worse than in 1844.^[2]
• Great Flood of 1951 — The 1951 flood was the second biggest in terms of discharge at 573,000 cubic feet per second (16,200 m³/s). The 1951 crest on July 14, 1951, was almost 2 feet (0.61 metres) lower than the 1844 flood and three feet lower than the 1993 flood. However, the flood was the most devastating of all modern floods for Kansas City since its levee system was not built to withstand it. It destroyed the city's stockyards and forced the building of an airport away from the Missouri River bottoms.
• Great Flood of 1993 — The 1993 flood was the highest recorded but had a lower rate of discharge at 541,000 cubic feet per second (15,300 m³/s). While the 1993 flood had devastating impacts elsewhere, Kansas City survived it relatively well because of levee improvements after the 1951 flood.