Miss. Code Ann. § 59-9-49: Miss. Code Ann. § 59-9-49

In addition and supplemental to the rights, duties and powers now or hereafter conferred by law upon counties having created a county port authority or county development commission, the board of supervisors of any such county, at the request of the county port authority or the county development commission, is authorized and empowered, in its discretion, to levy an ad valorem tax, not to exceed two mills on the dollar of assessed valuation of the taxable property of such county, to provide an operating fund for such county port authority or county development commission.