[2] The county is named in honor of James Monroe, the fifth President of the United States.

[3] Part of the county east of the Tombigbee River originally made-up part of the Alabama Territory, belonging to Marion County, until new lines of demarcation put it in the State of Mississippi in 1821.

[4] In 1889, an African-American man, Keith Bowen was lynched by a mob in the Lebanon community six miles south of Aberdeen after he was found in a white girl's bedroom at 3:00 AM.

"[5] In 1922, William Baker, an 18-year-old African-American man was lynched in Monroe County by a white mob.

[8] As of the 2020 United States Census, there were 34,180 people, 13,966 households, and 9,122 families residing in the county.

[8] At that time, oat crops typically yielded forty to sixty bushels per acre.

[8] Other crops grown, either for harvest or pasture, included wheat, rye, barley, rape, cotton, Japan clover.