George Dudley Seymour State Park is a public recreation area occupying 222 acres (90 ha) on the east bank of the Connecticut River in the town of Haddam, Connecticut.

[3] The park was once the site of Clarkhurst, the estate of wealthy Higganum harrow manufacturers George, Henry and Thomas Clark.

In addition to living at Clarkhurst, the family used the land as a testing ground for agricultural equipment.

Henry Clark's daughter, who took possession in 1921, sought to develop the site for recreational use but the property saw steady decline with the coming of the Great Depression.

It was owned by Marion Gutherie from 1942 until 1960, when it was purchased by the state for $60,000 using funds provided by the George Dudley Seymour Foundation.