Missouri Constitution
Article VI - Local Government
Section 18(b) Provisions required in county charters—exception.

The charter shall provide for its amendment, for the form of the county government, the number, kinds, manner of selection, terms of office and salaries of the county officers, and for the exercise of all powers and duties of counties and county officers prescribed by the constitution and laws of the state; however, such charter shall, except for the charter of any county with a charter form of government and with more than six hundred thousand but fewer than seven hundred thousand inhabitants, require the assessor of the county to be an elected officer.

(Amended August 8, 1978) (Amended November 8, 1994) (Amended April 4, 1995) (Amended November 2, 2010)