Pyractomena ecostata is an uncommon firefly primarily associated with brackish tidal marshes of the Atlantic and Gulf coasts of Florida. A geographically isolated occurrence is known from coastal southern New Jersey. Herein, we report 2 unpublished locality records from Kent County, DE, that expands the range of the Mid-Atlantic population into the Delaware Bay Estuary. We also report a previously unpublished modern-day record from Cape May County, NJ, perhaps the first New Jersey specimen secured since 1898. These data bring the total known number of Mid-Atlantic collection sites to 6. Although the species is very rare in the Mid-Atlantic, the disjunct population remains extant and therefore should be considered a significant inventory and conservation target due to impending sea-level rise and the spread of the invasive Phragmites australis (Common Reed).