With the help of Potawatomi chief Johnny Green, Anson persuaded early settlers to stay in the area.

In 1863 the title of county seat transferred from the village of Marietta to Marshalltown.

Marshalltown plays a small but significant role in the life of Ebe Dolliver, a main character in MacKinlay Kantor's Pulitzer Prize-winning novel "Andersonville" (1955).

Adrian Constantine "Cap" Anson, son of Henry and Jennette Anson, was the first European child born in the new pioneer town and is today known as Marshalltown's “first son.” Adrian became a Major League Baseball player and was inducted into the National Baseball Hall of Fame in 1939.

Adrian's brother Sturgis also became a talented baseball player and both went to play on intra-school teams at the University of Notre Dame.

In 1870 Marshalltown played an exhibition game with the talented Rockford Forest Citys.

Although Marshalltown lost the game, Rockford's management offered contracts to all three of the Ansons.

Adrian accepted the contract, which began his professional career in baseball in 1871.

It damaged numerous structures in the area, causing $1 million (1961 USD) in the town alone.

[13] Marshalltown would be hit again on July 19, 2018, when another EF3 tornado with peak winds of 145 mph moved directly through downtown at 4:37 p.m. local time.

[14] On August 10, 2020, Marshalltown was hit by a powerful derecho, which caused extensive damage throughout the city.

[18][19] The damage to public parks in the city and surrounding Marshall County was "extensive", particularly to trees.

[20] Marshalltown's Hispanic population in particular boomed in the 1990s and 2000s with immigrants mostly from Mexico, just like in many other Midwestern towns with meat-packing plants.

[22] Federal law enforcement have twice raided the Swift & Company (now JBS) meatpacking plant, first in 1996 and again in 2006, arresting suspected undocumented immigrants for alleged identity theft.

[24] Explaining the 2006 raid's effect on the community, Police Chief Michael Tupper told The Washington Post in 2018 that “I think that there’s just a lot of fear that it could happen again.

Not just for the families and people that were directly impacted, but for our school system, for our local economy, for our community as a whole.

[26] Neighboring counties include Hardin and Grundy to the north, Tama to the east, Jasper to the south, and Story to the west.

[37] In 1874, high school classes were held in an old building on North Center Street.

East Marshall Community School District serves small portions of the Marshalltown city limits.

[39] The BCLUW Community School District serves some rural areas nearby Marshalltown.

An expressway, Iowa Highway 330 connects Marshalltown to Des Moines.

A municipal airport serves the county, approximately four miles north of town.

Construction of the Cedar Rapids and Missouri River Railroad reached Marshalltown in 1862.