Union Chapel, also known as Mitchell Hollow Union Chapel, is a historic chapel on Mill Road in Windham, Greene County, New York. It was built in 1897 and is a one-story, three by three bay, wood-frame structure resting on a stone and concrete foundation. It is sheathed in narrow clapboards and features a fully pedimented portico and a two-stage bell tower. It was built by the local Methodist Episcopal and Presbyterian congregations.
It was added to the National Register of Historic Places in 2001.