Planting Fields Arboretum State Historic Park is an arboretum and state park covering over 400 acres (c. 1.6 square kilometres) located in Upper Brookville, New York. It lies between Upper Brookville and Locust Valley on New York, USA's Long Island.
Near the end of America's Gilded Age, the estate named Planting Fields was the home of William Robertson Coe, an insurance and railroad executive, and his wife Mary "Mai" Huttleston (née Rogers) Coe, the youngest daughter of millionaire industrialist Henry H. Rogers, who had been a principal of Standard Oil. It includes the sixty-five-room Coe Hall, greenhouses, gardens, woodland paths, and outstanding plant collections. Its grounds were designed by Guy Lowell, A. R. Sargent, the Olmsted Brothers, and others. Planting Fields also features an herbarium of over 10,000 pressed specimens.
The name "Planting Fields" comes from the Matinecock Indians who cultivated the rich soil in the clearings high above Long Island Sound.