Contacting a commissioner or politician of any sort can be intimidating, as there are different honorifics that may be used depending on the method by which you are greeting them. In the case of a county commissioner, the honorific or prefix you use will differ, depending on whether you are speaking to the commissioner in person, on the phone or by letter.
Address the county commissioner in person or on the phone with the honorific "Commissioner" and his last name. For example, "Hello, Commissioner Black."
Open a letter to a county commissioner with the appropriate prefix and the honorific "Commissioner." For example, "Dear Mr. Commissioner." A less formal approach is to omit the prefix and use the commissioner's last name, such as "Dear Commissioner Black."
Address an envelope to a country commissioner using the honorific "The Honorable," followed by his full name. For example, "The Honorable John Black."