If you wish to write a Michigan U.S. Senator:

United States Senate

Levin, Carl - (D - MI)    
269 Russell Senate Office Building
Washington DC 20510
(202) 224-6221
Web Form: levin.senate.gov/contact/

Stabenow, Debbie - (D - MI)    
133 Hart  Senate Office Building
Washington DC 20510
(202) 224-4822
Web Form: stabenow.senate.gov/email.cfm