A questionable folk etymology claims that after the United States acquired the region, a long-winded discussion over renaming the Río Hondo was ended by a frustrated francophone who suggested "name it quelque-chose" (English: 'anything'), which was recorded as "Calacasieu.

"[4] A similar dubious folk etymology relies upon the French quelques choux (English: 'some cabbages').

[5] Various spellings of 'Calcasieu' are found in early French- and English-language sources, including Calcasutt, Culqueshoe, Culkeshoe, Kelke-chute, Quelqueshue, Calcasu, Calcasiu, Quelqueshoe, and Calcasiew.

The earliest version of the name—rivieére Calkousiouk—was published in 1807 by French explorer Charles César Robin [fr].

[5] The early history of the parish dates to the period of the Spanish occupation of Louisiana, after France had ceded this territory following its defeat by Great Britain in the Seven Years' War.

The area became a refuge for outlaws and filibusters from Carolina, Georgia, and Mississippi of the United States, which had recently gained independence from Great Britain.

By an act of Congress, approved on March 3, 1823, this strip of land was attached to the district of the Louisiana Territory south of the Red River.

Early settlers to the area included the Ryan, Perkin, Hodges, Bilbo, LeBleu, Deviers, and Henderson families.

Of French descent and exiled by the British from Acadia (eastern Canada), many of these refugees had settled in Louisiana.

Data compiled from historical volumes of the US Center of Population and Housing indicate that in 1850, 240 of 3914 Parish residents were "Free Men of Color".

"[3] On August 24, 1840, six men met at a private home near present-day Chloe to organize as the parish police jury representing six wards.

Finally in 1852, Jacob Ryan was successful in having the parish seat relocated from Marion to the east bank of Lake Charles.

It was one of several parishes organized during the Reconstruction era by the Republican-dominated legislature, in an effort to build Republican strength.

Although the parish had been larger in land mass than the states of Delaware and Rhode Island it was primarily utilized as grazing land for cattle with no significant plantings of cotton, sugar cane or other crops requiring the utilization of slave labor.

[7] Therefore, Calcasieu before the Civil War was home to a lower percentile of African-American slaves than many other parts of the State.

In 1912, "Imperial Calcasieu" was further divided with the creation of the three new parishes of Allen, Beauregard, and Jefferson Davis, with a total area of approximately 2,548 square miles (6,600 km2).

Following these jurisdictional changes, Calcasieu Parish lost almost half of its population between the 1910 and 1920 United States census.

Each district elects one Juror for representation, in keeping with the ruling by the U.S. Supreme Court of the "one man, one vote" principle.

This can change the boundaries of the single-member districts, to ensure that each Juror represents approximately the same number of people.

A 2003 report found that the office of the public defender in Calcasieu Parish used an expert in only 1 of 171 cases.

[17] The first courthouse erected at Marion, a crudely built log cabin, was completed in August 1841.

When the seat of justice was changed to Lake Charles in 1852, Sheriff Jacob Ryan with the help of his slave, Uncle George, and the aid of his good friend and fellow landowner, Samuel Adams Kirby, loaded the log cabin courthouse on an ox cart and transported the small building through the piney woods to Lake Charles.

[20] Elements of the 256th IBCT and the 139TH RSG (Regional Support Group) are based in Lake Charles.