Karen Mitchoff – District IV Supervisor » CBCA Members Go back to directory. Add to Address Book. Karen Mitchoff – District IV Supervisor Karen Mitchoff – District IV Supervisor Home 2151 Salvio St. Suite R Concord CA 94520 home Work Phone: (925) 521-7100work Website: http://www.co.contra-costa.ca.us/6291/District-lV-Supervisor-Karen-Mitchoff No Image Available