Archeological evidence indicated the spit has developed across Drayton Harbor over the last 4000 to 5000 years (Grabert & Schwartz, 1972).
Ice Age Boulders in Drayton Harbor (washingtonlandscape.blogspot.com) Drayton Harbor is a shallow bay just south of the Canadian border. The City of Blaine is located on its northeast and southwest sides such that the small city has two parts separated by the bay.
https://github.com/davepinch/pinchy.cc/blob/master/content/topics/places/bays/drayton-harbor/drayton-harbor.md
At the northern most reach of Whatcom County’s shoreline is a spit approximately 2000 meters long trending northeasterly from the north side of Birch Point (fig.2.). The spit separates Drayton Harbor from Semiahmoo Bay and provides some protection for small boats and shoreline developments within the bay.