 In North Hudson , the valley becomes less pronounced as the Schroon River reaches its source near exit 30 . Here , US 9 and I @-@ 87 cross paths again , with the former heading northwest toward Keene and the latter continuing northeast in a narrow valley formed by Ash Craft Brook . After 5 miles ( 8 @.@ 0 km ) , the stream reaches its source at Lincoln Pond , leaving the Northway to climb in elevation and wind its way northeastward across the surrounding mountains . It reaches slightly more level ground in Westport , where I @-@ 87 connects to NY 9N at exit 31 . From here , the highway takes a generally northerly track across the Bouquet River to the town of Lewis , rejoining US 9 as both roads head toward Clinton County . They split again after 7 miles ( 11 km ) as US 9 veers more easterly than I @-@ 87 to serve Keeseville . The Northway , meanwhile , heads to the northwest , bypassing the village to cross the Ausable River and enter Clinton County . 
