Black Diamond is a city in King County, Washington, United States. The population was 4,697 at the 2020 census. In 2022, with a 35% growth rate, Black Diamond was the fastest growing small city in King County.
AdShop Quality Apparel & More From BlackDiamond® - Your Next Adventure Awaits. Gear to Get You Outside - Shop Apparel & More + Free Shipping on Orders $99+.
Outdoor Equipment Leader · Innovative Equipment · 60+ Years of Experience