In August of 1808, Horatio Gates Onderdonk was born of Joseph and Dorothy Onderdonk. In 1829, Onderdonk graduated from Columbia College and went on to become a merchant in NYC. Afterwards, Onderdonk became the county judge of King County, and began construction in 1836 on his house in Manhasset. Horatio would raise his three children with his wife Elizabeth in this house.In 1980, the House was identified as a Town of Hempstead Landmark. The House is currently owned by the Strathmore Association Inc. The Onderdonk House was the perfect example of the developments that were occurring in Manhasset and the greater New York area during the early 19th century. Families with high amounts of wealth would settle in Manhasset which granted easy access to New York City. Despite many of these lavish houses being destroyed, the Onderdonk House characterized an important aspect of the significance of Manhasset that remains a prevalent part of Manhasset culture to this day.