▁Virginia . ▁ ▁The ▁survey ors ▁also ▁fixed ▁the ▁boundary ▁between ▁Del aware ▁and ▁Pennsylvania ▁and ▁the ▁approximately ▁north – s outh ▁portion ▁of ▁the ▁boundary ▁between ▁Del aware ▁and ▁Maryland . ▁Most ▁of ▁the ▁Del aware – P en nsylvan ia ▁boundary ▁is ▁an ▁arc , ▁and ▁the ▁Del aware – M ary land ▁boundary ▁does ▁not ▁run ▁truly ▁north – s outh ▁because ▁it ▁was ▁intended ▁to ▁bis ect ▁the ▁Del mar va ▁Pen ins ula ▁rather ▁than ▁follow ▁a ▁mer id ian . ▁ ▁The ▁Maryland – P en nsylvan ia ▁boundary ▁is ▁an ▁east – west ▁line ▁with ▁an ▁approximate ▁mean ▁latitude ▁of ▁ 3 9 ° 4 3 ′ 2 0 ″   N ▁( Dat um ▁W GS   8 4 ). ▁In ▁reality , ▁the ▁east - west ▁Mason – D ixon ▁line ▁is ▁not ▁a ▁true ▁line ▁in ▁the ▁geometric ▁sense , ▁but ▁is ▁instead ▁a ▁series ▁of ▁many ▁ad jo ining ▁line ▁segments , ▁following ▁a ▁path ▁between ▁latitude ▁ 3 9 ° 4 3 ′ 1 5 ″   N ▁and ▁ 3 9 ° 4 3 ′ 2 3 ″   N . ▁ ▁The ▁survey ors ▁also ▁extended ▁the ▁boundary ▁line ▁ ▁west ▁of ▁Maryland ' s ▁western ▁boundary , ▁into ▁territory ▁that ▁was ▁still ▁in ▁dispute ▁between ▁Pennsylvania ▁and ▁Virginia , ▁though ▁this ▁was ▁contrary ▁to ▁their ▁original ▁char ter . ▁Mason ▁and ▁D ixon ' s ▁survey ▁was ▁finished ▁on ▁October   9 , ▁ 1 7 6 7