Description: Blockhouse 1 : 1814, NYC, Central Park, near 7th Ave entrance at 110th Street. May be same as Fort Clinton (4) near 5th and 107th. Blockhouse 2 : 1814, NYC, South side of 114th Street west of Morningside Avenue. Blockhouse 3 : 1814, NYC, South side of 121st Street west of Morningside Avenue. Blockhouse 4 : 1814, NYC, South side of 123rd Street near 10th Avenue in Morningside Park. The ruins of Blockhouse #4 marked Morningside Park's northern end at Amsterdam Avenue until Public School #36 was built there in 1967. Picture from 1903 shows ruins at top of 123rd Street cut (left/South). Early 1877 etching of this view can be found at Fort Laight entry. Info credit to Eric K. Washington, The Manhattenville Heritage Society Upper Boundry of Montaign'e Flat, view west down 123rd street toward Hudson River. Source: New Harlem, Past and Present, by Carl Horton Pierce, 1903. (Grant's Tomb in background.)