 Another gap in I @-@ 87 existed in downstate New York , as the plan to build I @-@ 87 along the proposed Hudson River Expressway had been scrapped by 1962 . Instead , I @-@ 87 was now proposed to begin in Port Chester and follow a new routing through Purchase , Armonk , and Katonah to Brewster , where it would join I @-@ 84 . The routing was modified slightly by 1968 : I @-@ 87 still began in New York City , then overlapped with I @-@ 287 east to Purchase . From there , I @-@ 87 headed north along the now @-@ open expressway to Armonk , where it ended at NY 22 . Another portion of the highway , from Goldens Bridge ( NY 138 ) to Brewster , was open as well while the part from Armonk to Katonah was under construction . This segment , as well as the part from Katonah to Goldens Bridge , was completed by 1971 . On January 1 , 1970 , I @-@ 87 was rerouted between Elmsford and Newburgh to follow the mainline of the Thruway instead , leaving the Purchase – Brewster freeway to become I @-@ 684 . 
