Some of the trees on the island seem to be over 150 years old.........I really am not sure about that...........but many look older than 1881.......


After a disastrous flood in 1881, the United States Army Corps of Engineers dredged a deep channel in the Potomac and used the material to fill in the Potomac (creating the current banks of the river) and raise much of the land near the White House and along Pennsylvania Avenue NW by nearly 6 feet (1.8 m).^[7][8][9] Much of the dredged material was used to build up the existing tidal flats in the Potomac River as well as sandbars which had been created by silting around Long Bridge.^[10] Reclamation occurred in three phases: Section 1 (what is now 135-acre (550,000 m²) West Potomac Park), section 2 (what is now the 277-acre (1,120,000 m²) area around the Tidal Basin), and section 3 (what is now 327-acre (1,320,000 m²) East Potomac Park).^[11] Congress formally designated these areas "Potomac Park" on March 3, 1897.^[12]