Welcome to Diamond K Supply. As a family-owned business, we truly appreciate the loyalty of our customers and employees. With over fifty years of experience behind us, the Magrath family looks forward to serving our customers and community for years to come. In 1936, Diamond K Supply Co first opened its doors in Lafayette at 3671 Mt. Diablo Blvd. and is one of Lafayette's oldest continuously operated businesses. Lafayette was much smaller and more rural in those days. Mt. Diablo Blvd was Highway 24 and only one lane in each direction. To serve the rural needs of the community, Lafayette resident Ogden Kiesel opened Diamond K Supply Co as a feed and fuel store selling hay, feed, firewood, and coal. To name the store, Ogden Kiesel used a livestock brand in the name and placed the Kof his last name within a diamond resulting in the brand of. Diamond K Supply Co was born. In 1947, World War II veteran Bill Magrath and his wife, Nancy, purchased an interest in Diamond K where Bill Magrath spent the next 43 years managing and expanding the business he loved. Soon, Bill and Nancy Magrath assumed full ownership of the business and the Magrath family has proudly owned and operated Diamond K Supply since 1948. In addition to Bill and Nancy, all members of the Magrath family have worked at Diamond K at one time including daughter Anne Magrath Coleman, and sons Bill Magrath and Miler Magrath. In recent years, Diamond K became Diamond K Supply, Ltd, a California corporation, but the Magrath family still owns and operates this business. Miler Magrath has been President of the company since 1990. Over the years, Diamond K has expanded its facilities, increased its delivery capability, and increased its products, to keep up with the needs of our customers. On this website, we hope to introduce you to several of our products and our ability to meet the needs of each of our customers. The Magrath family and all of our employees are eager to serve you. Just come into our store or give us a call.