Amite County, established in 1809, was the fifth county formed in the Mississippi Territory. In 1799, Mississippi Territorial Governor Sargent issued a proclamation dividing the original Natchez Territory into the southern or lower division, to be called the County of Adams, and the northern or upper division to be called Pickering. In 1802 Wilkinson County was established from Adams County; in this same period of time, Jefferson and Claiborne counties were established from Pickering County On February 24, 1809, the general assembly of the Mississippi Territory enacted the division of Wilkinson County and the establishment of Amite.
The name Amite was given because of the river by that name which flows through the county which had been named by the French in commemoration of the friendly manner in which they had been received by the [Houma] Indians living along the river.