The current McLean County State's Attorney is Ladd R Erickson of Washburn. He was first elected to the four year position in 2002 and was re-elected in 2006, 2010, 2014, 2018, and 2022. The State's Attorney serves as the official legal representative of the county. McLean County's State's Attorney is a full-time position and the individual holding the office does not engage in the private practice of law.

The State's Attorney also:

• Serves as public prosecutor and starts prosecutions when a crime has been committed;
• Attends and gives advice to grand juries;
• Defends and prosecutes all legal cases in which the state or county may be a party;
• Gives advice to county, township and school district officers; and
• Serves as the legal adviser for the county commission and elected county officials.

The States Attorney's Office has two additional employees, Karissa Rittenbach, who serves as Legal Assistant II and Kelsey Renner serves as Legal Secretary/Clerk.