St. George's Manor was a large tract of land purchased by William "Tangier" Smith in the 1600s on Long Island. Parts of the original parcel, which was approximately 64,000 acres of land, are preserved in bits and pieces.  The northwestern section of the estate was known as "The Swamp" or "Long Swamp." This parcel of is now called the Longwood or Smith Estate and is located in Ridge.
Occupied by members of the Smith family for over 150 years, Helen Tangier Smith, who never married, was the last of her line and she devoted much of her time to organizing the family papers and mementoes. She hoped that at some time Longwood would be preserved and its history recorded. Miss Helen died in 1955. She willed Longwood to her cousin, Elbert Smith from California and he uprooted his wife and five children and moved east to reside at the old manor house. He wanted to have Longwood preserved, but his untimely death in 1967 prevented him from accomplishing this. His widow, Eleanor returned to California and the property was put on the market and sold to Levitt and Company, real estate developers. The contents of the house were sold at auction in 1968. Longwood estate was slated for the wrecking ball.

The land and the house were next purchased in 1973 by Wilbur F. Breslin who proposed the development of a huge residential and commercial complex. Concerned citizens and members of the Town government urged the preservation of Longwood. In a generous gesture, Mr. Breslin presented the house and thirty five acres of land to the Town of Brookhaven in 1974.
Now safe from destruction, Longwood Estate has been included in the National Register of Historic Places.