The Blytheville, AR Micropolitan Statistical Area includes all of Mississippi County.

Local oral tradition held that prior to the major earthquakes of 1812, the lands in Mississippi County were higher in elevation compared to now and were not prone to flooding.

[3] Though the earthquake was named for New Madrid, Missouri, as that was the only town in the area with any population, the actual epicenter of the quake was three miles below what is now Blytheville, Arkansas.

The first county seat was a small community called Cornwall, which was located at on the banks of the Mississippi River, on the remains of an old Spanish "encampment."

[6] During World War 2, a B-25 pilot training school was constructed at Blytheville, with satellite landing strips at Manilla and in the Missouri Bootheel.

[9] As of the 2020 United States Census, there were 40,685 people, 16,389 households, and 10,635 families residing in the county.

Formerly a traditionally Democratic area, Mississippi County has voted Republican in the past five presidential elections.

The economy of Mississippi County transitioned from agriculture (especially cotton) to manufacturing (mostly steel production) beginning in the 1980s.

Company executives have also praised the work ethic of the rural farm families of the area as a natural fit for ironworkers.

Mississippi County, Arkansas is placed in the Memphis, TN Television Market.

Each township includes unincorporated areas; some may have incorporated cities or towns within part of their boundaries.

However, the United States census does list Arkansas population based on townships (sometimes referred to as "county subdivisions" or "minor civil divisions").

Each town or city is within one or more townships in an Arkansas county based on census maps and publications.