NY 23B forks from its parent, NY 23, south of the city of Hudson and a half-mile (0.8 km) east of the Rip Van Winkle Bridge in Greenport, Columbia County. The intersection borders the grounds of the Olana State Historic Site and is west of the Columbia-Greene Community College campus. NY 9G, concurrent with NY 23 west of this point, leaves NY 23 to follow NY 23B toward Hudson. The route is the westernmost through route along the Hudson River between the Rip Van Winkle Bridge and Hudson; however, it is separated from the river by Mount Merino, a peak situated above sea level. From NY 23, the two-lane road heads northeast through rural, wooded areas until it reaches the city of Hudson.