The Judge of the St. Peters Municipal Court is known as a Municipal Judge of the Eleventh Judicial Circuit Court. The Municipal Court Code Chapter 130 provides that the Municipal Court shall be subject to the rules of the Circuit Court of which it is a part and to the rules of the State Supreme Court.

The Municipal Judge shall make and adopt rules of practice and procedure necessary to hear and decide matters pending before the Municipal Court, and implement and carry out the provisions of the Missouri Rules of Practice and Procedure in Municipal and Traffic Courts. The Municipal Judge shall have other powers, duties, and privileges as prescribed by State Law or other ordinances of the City.

Elected April 2007 to serve a four-year term, Donald L. Kohl has served as the Judge of the City's Municipal Court since August 1985. The Municipal Court handles over 20,000 cases per year and manages revenues of over $2 million.

Judge Kohl graduated from the University of Missouri, Columbia in 1976 and from Washington University School of Law in 1979. He is a founding partner in the law firm Shea, Kohl, Alessi and O'Donnel, LC. He is a member of the St. Charles County Bar Association, the Missouri Bar, The Missouri Association of Trial Attorneys and the Illinois State Bar Association.