Member Directory

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 new store’s name and placed the “K” of his last name within a diamond resulting in the red Diamond K brand that we use as our Logo. 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. Even though our founders, Bill and Nancy Magrath, have passed, the Magrath family still owns and operates this business. Miler Magrath was President of the company starting in 1990 until his passing in 2017. Bill Magrath is the current President and General Counsel to the company. Anne Magrath Coleman is the current Vice-President.



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.
- Landscape Supplies

Family Owned and Operated Christmas Tree lot in Lafayette for over 20 years. The Owner Tommy was born and raised in Lafayette.
- Landscape Supplies
- Nursery