Averill Park is a census-designated placein Rensselaer County, New York, United States. The population was 1,693 at the 2010 census.The community is named after landowner Horace Averill. It is located within the town of Sand Lake on Route 43. The community is south of Crystal Lake and east of the town of West Sand Lake.The Sand Lake Baptist Church was listed on the National Register of Historic Places in 2004.