Based on documentary records, Augustin Langlois was born on February 5, 1692, in Charlesbourg, Quebec. He was a voyageur engaged in the Indian trade, and he and two brothers, Etienne and Louis, left Canada for the new Louisiana colony to seek their fortune by the 1720s. He was apparently first in Mobile, where he married a woman named Marie-Catherine Baudreau, also called Graveline. She had been born in Detroit to parents making the journey from French Canada to Mobile while they were in transit. The Langlois brothers arrived in New Orleans and apparently received tracts on the Bienville concession by 1728, but they seem to have spent considerable time in the city proper, showing up in notes of indebtedness there. Augustin was petitioned for payment by a creditor of Nicolas La Riviere for 200 livres in 1728, due on purchase of a lot, perhaps the Royal Street one. In 1737 he received property in Prairie du Rocher, back in the Illinois country in the vicinity of Kaskaskia, and appears to have departed soon afterwards. He died there in 1749, at the age of 57; his wife apparently remarried and later relocated to the Opelousas district.