Minn. Const. art. XII, § 2

Every law which upon its effective date applies to a single local government unit or to a group of such units in a single county or a number of contiguous counties is a special law and shall name the unit or, in the latter case, the counties to which it applies. The legislature may enact special laws relating to local government units, but a special law, unless otherwise provided by general law, shall become effective only after its approval by the affected unit expressed through the voters or the governing body and by such majority as the legislature may direct. Any special law may be modified or superseded by a later home rule charter or amendment applicable to the same local government unit, but this does not prevent the adoption of subsequent laws on the same subject. The legislature may repeal any existing special or local law, but shall not amend, extend or modify any of the same except as provided in this section.