Otter Kill is a 16.0-mile-long (25.7 km) tributary of Moodna Creek that flows through central Orange County, New York, in the United States. Via the Moodna, which it forms at a confluence with north of the village of Washingtonville, its waters eventually reach the Hudson River. The Otter Kill flows primarily through rural, undeveloped areas of the towns of Goshen, Hamptonburgh and Blooming Grove. Development pressures in those areas have led the state Department of Environmental Conservation to classify it and a major tributary, Black Meadow Creek, as threatened streams.