- Washington State Route 539 (Wikipedia)
State Route 539 (SR 539, named the Guide Meridian) is a north–south state highway in the U.S. state of Washington. The highway travels through northwestern Whatcom County and connects Interstate 5 (I-5) in Bellingham with Lynden and the Canadian border near Langley, British Columbia.
Mount Baker, WA simplified hazards map (usgs.gov)