Moravian settlers in NC were the first Americans to officially celebrate the 4th of July.
That, plus the Moravian fondness for documenting everything, gives Salem its claim to the first-ever Fourth of July celebration.
1550s (n.); 1610s (adj.), from Moravia. From 1746, in reference to the Protestant sect founded in the former German state of Moravia (now in Czech Republic). Related: Moravianism.