Miss. Code Ann. § 65-23-327

The exercise of the powers conferred by this article constitute the performance of essential governmental functions, and as bridges which are owned and operated by counties constitute public property used for public purposes, such bridges shall at all times be free from taxation within the state. No county shall be required to pay taxes or assessments upon any such bridge or any part thereof owned by it, and bonds issued under the provisions of this article, their transfer, and the income therefrom shall at all times be free from taxation within the state.