Grayslake Police Department 10 S Seymour Ave, Grayslake, IL60030 The Grayslake Police Department is a community-focused department that ensures the safety and welfare of local residents…More and businesses. The department is accredited by the Commission on Accreditation for Law Enforcement Agencies (CALEA), a recognition that fewer than 60 departments statewide have achieved. The 35 officers and six civilian employees aim to respond quickly and effectively to community issues. The department moved into a new, state-of-the-art facility on July 1, 2008. It is attached to the Grayslake Village Hall.