Beyond the interstate it continues southwest alongside the base of the northern slopes of Fishkill Ridge, the northernmost end of the Hudson Highlands. It detours slightly to the north near Glenham and then resumes its southwesterly course as it flows into the city of Beacon, where it passes through the eastern section of the city in a narrow valley with the Beacon Line running along its shore. There are many rapids and waterfalls as it descends more sharply to the Hudson. Here it receives its last tributary, Dry Brook, which drains Beacon Reservoir on the ridgetop.