Neponset River Postcards Neponset River No. 1021 Postcard. Caption on front: Neponset River, Mattapan, Mass. Postmarked Dedham with one cent stamp. On verso: No. 1677. Pub. by Boston Post-Card Co. Hand-colored. Facebook Twitter Print Friendly Skills Dorchester, Mattapan, Neonset River Posted on November 29, 2022 ← Mattapan Square Bridge over Neponset →