The Maryland/Delaware boundary and the Mason-Dixon Line divide Delmar. A double crown stone marker was erected in 1768 as the southern end of the only North-South portion of the Mason-Dixon line.
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In recognition of sport fishing's overall recreational and economic contributions to the state of Delaware and of the specific values of the weakfish (Cynoscion genus) as a game and food fish, the state Legislature adopted the weakfish as Delaware's State Fish.
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The Du Pont Laboratories first produced nylon at its plant in Seaford, Delaware. This earned the town the distinction of being the Nylon Capital of the World.
