Bioregion. Orcas Island is located in the center of the San Juan Archipelago in Northwestern Washington State, USA. These islands are in the rain-shadow of the Olympic Mountains and have lakes, marshes, and fertile valleys.This gives us a climate very conducive to horticulture.ioregion. Orcas Island is located in the center of the San Juan Archipelago in Northwestern Washington State, USA. These islands are in the rain-shadow of the Olympic Mountains and have lakes, marshes, and fertile valleys. This gives us a climate very conducive to horticulture.