On October 18, 1767, Charles Mason and Jeremiah Dixon complete their survey of the boundary between the colonies of Pennsylvania and Maryland as well as areas that would eventually become the states of Delaware and West Virginia. The Penn and Calvert families had hired Mason and Dixon, English surveyors, to settle their dispute over the boundary between their two proprietary colonies, Pennsylvania and Maryland.

In 1760, tired of border violence between the colonies’ settlers, the British crown demanded that the parties involved hold to an agreement reached in 1732. As part of Maryland and Pennsylvania’s adherence to this royal command, Mason and Dixon were asked to determine the exact whereabouts of the boundary between the two colonies. Though both colonies claimed the area between the 39th and 40th parallel, what is now referred to as the Mason-Dixon line finally settled the boundary at a northern latitude of 39 degrees and 43 minutes. The line was marked using stones, with Pennsylvania’s crest on one side and Maryland’s on the other.

Air Quality Alert issued October 16 at 1:44PM PDT by NWS Seattle

…AIR QUALITY ALERT IN EFFECT UNTIL 11 AM PDT MONDAY…

An Air Quality Alert for Smoke has been issued by the following agencies: Olympic Region Clean Air Agency Puget Sound Clean Air Agency Washington State Department of Ecology until 11 AM PDT Monday.

The air quality is expected to be unhealthy for sensitive groups to unhealthy. The air quality along the Cascade Valleys may be further diminished during this period. Everyone, especially sensitive groups, should limit time spent spent outdoors, avoid strenuous activities outdoors, and choose light indoor activities.

For current air quality conditions, health precautions, and additional information visit your local air quality agency at http://www.orcaa.org, http://www.pscleanair.gov, and ecology.wa.gov.