[1] The county was named after Frank J. Marshall, a state representative who operated the first ferry over the Big Blue River.

The infamous Donner Reed Party rested along the banks of the Big Blue river and lost one of its members, Sarah Keyes, who is still buried at Alcove Springs (located outside of Marysville).

Many documented pioneer bodies are buried surrounding Alcove Springs.

He moved his ferry business to an upper crossing now known as Marysville (the city is named after Marshall's own wife Mary).

This tornado measured F4 on the Fujita scale and had a damage path 800 yards (730 m) wide and 100 miles (160 km) long.

Marshall County was a prohibition, or "dry", county until the Kansas Constitution was amended in 1986 and voters approved the sale of alcoholic liquor by the individual drink with a 30 percent food sales requirement.

[16] † means a community is designated a Census-Designated Place (CDP) by the United States Census Bureau.

The city of Marysville is considered governmentally independent and is excluded from the census figures for the townships.