Sparkill, formerly known as Tappan Sloat, is a suburban hamlet and census-designated place in the Town of Orangetown, Rockland County, New York, United States located north of Palisades; east of Tappan; south of Piermont and west of the Hudson River. As of the 2010 census, the CDP had a population of 1,565. The hamlet is home to St. Thomas Aquinas College and the Dominican Sisters of Sparkill.