The county-designated highways in Michigan comprise a 1,241.6-mile-long (1,998.2 km) system of primary county roads across the US state of Michigan. Unlike the State Trunkline Highway System, these highways have alphanumeric designations with letters that correspond to one of eight lettered zones in the state. The County-Designated Highway System (CDH System) was created in 1970 in response to the business concerns of a woman from Saugatuck. Her one-woman crusade in the 1960s started after the highway in front of her motel was turned over to local control as a county road and removed from state highway maps when the nearby freeway opened. After nearly a decade of efforts, the first two test highways were designated, one each in the Lower and Upper peninsulas of the state and included on th