Though the line did not actually divide North and South, it became the symbolic division between free states and slave states. Today, it still stands for the boundary between northern and southern states.
An Americanism dating back to 1770–80
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
The Huntington’s array of early American maps includes those marking the Mason-Dixon line, the geographical star of his 1997 historical novel, “Mason & Dixon.”
From Los Angeles Times ● Dec. 14, 2022
"Below the Mason-Dixon line . . . We don't have just one of two ways of cooking succulent sweet potatoes," Schuyler wrote.
From Salon ● Nov. 22, 2022
The change was particularly pronounced in a swath from about the Mason-Dixon line to just north of Detroit, Chicago, and Nebraska.
From Washington Times ● Dec. 17, 2021
Dixie is thought to be a reference to the Mason-Dixon line, although the origins of the term are still debated by historians.
From New York Times ● Jan. 20, 2020
On the map, the division line between slave and non-slave societies occurs in Virginia, broadly anticipating the Mason-Dixon line that later split slave states from free.
From "1491" by Charles C. Mann
My parents insisted I apply to colleges below the Mason-Dixon Line and on the east side of Texas.
From The Wall Street Journal ● Jan. 20, 2026
They are consumed with gusto and discrimination at nearly every party you might attend south of the Mason-Dixon Line, and although oblong and a bit thicker, they're sort of the grown-up version of a Cheez-It.
From Salon ● Jan. 22, 2023
The 19th century Mason-Dixon Line marked the boundary between slave states in the South and free states in the North.
From Seattle Times ● Jun. 24, 2022
A Black Democrat who served as governor and lieutenant governor south of the Mason-Dixon Line.
From Washington Times ● Nov. 12, 2021
Williams applied for engineering positions through the Civil Service but had been wary of moving to a state south of the Mason-Dixon Line.
From "Hidden Figures" by Margot Lee Shetterly
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
