Here is the short and simple version.
For a more complete study, we suggest you check out www.acadian-cajun.com. Cajun is the slang version of Acadian which came out of the French to English translation. Originally, French Catholics settled in the French colony of Acadia, modern day Nova Scotia. Britain took control of the region in 1713. Unable to get the Acadians to pledge allegiance to the crown, the British forced their deportation. This happened in waves with each wave going to different destinations, some to Canada, New England, and others to Louisiana.
These Acadians settled along the waterways west of the Mississippi River eventually spreading through the prairies to the western border of Louisiana and Texas. Cajun Country is locally referred to as Acadiana and is an officially recognized area of French-speaking parishes.