Battlefields of the American Revolution 

S486321 Set of 15 DCP 2025

First Day Cancel at Dedication Ceremony

special post office (tent) set up at National Park Service North Bridge Visitor Center Concord Massachusetts

Hand cancelled in a tent, may be few finger nail marks on some of envelopes from postal employee doing doing the canceling

Can email a copy of original receipt upon request for provenance

Which says

Battlefields of the American Revolution

174 Liberty Street 

Concord MA 01742

USPS 2407986500

That was a 1 day post office

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