 The gap in the Northway between Pottersville and Keeseville was narrowed considerably by July 1967 with the completion of a 25 @-@ mile ( 40 km ) segment from Pottersville to exit 30 at Underwood . It was closed further on July 25 , 1967 , with the opening of a 3 @-@ mile ( 4 @.@ 8 km ) stretch near Keeseville between exits 34 and 33 . The last section of the Northway to be built , a 30 @-@ mile ( 48 km ) stretch between Underwood and Keeseville ( exit 33 ) , was finished on August 31 , 1967 . The completion of the Northway linked New York City with Montreal by way of a direct , limited @-@ access highway , with I @-@ 87 becoming A @-@ 15 at the Canadian border . The total cost to build the Adirondack Northway was $ 208 million ( equivalent to $ 1 @.@ 48 billion in 2016 ) . 
