NY 149 officially begins at exit 20 on the northbound Adirondack Northway (I-87) in the town of Queensbury, from where it follows a ramp eastward to US 9. As signed, however, NY 149 begins at the southbound portion of I-87 exit 20 and follows County Route 23 (CR 23, named Gurney Lane) east to US 9, where it turns to follow US 9 northward. The signed and official routings join at the exit's northbound ramps. While concurrent with US 9, NY 149 passes the Adirondack/Lake George Factory Outlet Mall and several other businesses located on both sides of the highway. At the end of the factory outlets in the hamlet of French Mountain, NY 149 turns off US 9 and proceeds in a generally eastward direction toward the village of Fort Ann.