Manson is a city in Calhoun County, Iowa, United States.

[2] Manson was platted in 1872 on the Dubuque and Sioux City Railroad line.

[3] A destructive F4 tornado killed three people and destroyed a large part of Manson on June 28, 1979, at about 7:45 PM.

The tornado was on the southwest side of a large southeast-moving thunderstorm complex; thus, it was surrounded on three sides by clear skies (in fact, the sun was shining) and was highly visible.

The General Telephone Company exchange building for Manson was completely destroyed - the first time this had ever happened in Iowa.

The fact that it was still daylight also contributed to the relatively low death count from this destructive storm.

[5] According to the United States Census Bureau, the city has a total area of 3.18 square miles (8.24 km2), all land.

At one time, it was thought to be the biggest impact by an object from outer space in North America, until subsequent studies revealed larger examples.

The impact event was also once theorized to have led to the extinction of the dinosaurs, or contributed to it as a fragment of the Chicxulub meteor, until tests by the U.S. Geological Survey in 1991 and 1992 proved that it was too old by 9 million years.

Not much remains due to glacial till which has filled in the crater and has made it undetectable at ground level.

There were 857 housing units at an average density of 264.4 per square mile (102.1/km2).

[11] It was established on July 1, 1993, with the merger of the Manson and Northwest Webster districts.