Dean Cook Nationwide Insurance Agency Share: Insurance Dean Cook Nationwide Insurance Agency Visit Website 125 W. 5th St. Marysville, OH 43040 (937) 644-5015 (937) 644-5035 (fax) www.nationwide.com/dean-cook About About We have been in business for over 30 years. Greeting every customer with a smile, we provide exceptional customer service and the answer to all of your insurance needs.