- Western Terminus:
- NY 82 in Millbrook
- Eastern Terminus:
- Amenia Road (CT 343) at the New York-Connecticut state line
- 18.47 miles
NY 343 is an east/west route in Dutchess County. It begins at NY 82 in Millbrook and runs east to NY 22 in Dover Plains. It is then multiplexed with NY 22 north to Amenia. It splits off at the point where US 44 joins NY 22. From there, it runs east to the border with Connecticut, where it becomes Amenia Road (CT 343).