The rising Mississippi is a yearly occurrence in Adams County. With the current levee system in place, most years the flooding does little, if any, damage. There have been some major floods on record: 1903, 1909, 1912, 1913, 1944, 1960, 1965, 1973, 1985, and the great floods of 1993 and 2008.

The flood of 1965 broke through the levees and flooded the river bottoms. The flood of 1973 reached record levels but the levees held on the Illinois side of the river. The floodwaters broke through on the Missouri side inundating West Quincy, Missouri.

The great flood of 1993 caused major damage throughout the county. The Mississippi River reached flood stage on April 1, 1993 and remained above flood stage until September 4, 1993. It reached its peak at Quincy on July 13, 1993. Over $9,355,000 in damages was claimed by public entities within the county. FEMA and IEMA covered 90% of the damages in this disaster or $8,419,538. This still left the county to pay for the remaining 10% or $935,500.