 The village was first settled by Mennonites in the late 1920s, following the draining of Sumas Lake and the reclamation of the former lake bed for agriculture.Yarrow is at the foot of the Skagit Range of the Cascade Mountains on the Vedder River, near the latter's confluence with the Fraser, which traverses the Lower Mainland, of British Columbia.The Lower Mainland Ecoregion is part of the Pacific Maritime Ecozone.