Thiells, known as Thiell's Corner in the 1850s, is a hamlet and census-designated place in the town of Haverstraw, Rockland County, New York, United States. It is located north of Mount Ivy, east of Pomona, south of Tomkins Cove, and west of Garnerville. The population was 5,240 as of the 2020 census. During the American Revolution, Thiells was known as Haverstraw Forge, where General "Mad" Anthony Wayne, leading 1,350 Continental Army troops, was able to watch the area of Stony Point.