Roosevelt spent many summers of his youth on extended vacations with his family in the Oyster Bay area. In 1880, by then a young adult of 22, Roosevelt purchased 155 acres for $30,000 (equal to about $700,000 today) on Cove Neck. In 1881, his uncle James A. Roosevelt had designed his estate home several hundred feet west of the Sagamore Hill property. In 1884 Theodore Roosevelt hired the New York architectural firm Lamb & Rich to design a shingle-style, Queen Anne home for the property. The twenty-two room home was completed in 1886 for $16,975 (equal to $445,562 today), and Roosevelt moved into the house in 1887. Roosevelt originally planned to name the house "Leeholm" after his wife Alice Hathaway Lee Roosevelt. However, she died in 1884 and Roosevelt remarried in 1886, so he decided to change the name to "Sagamore Hill". Sagamore is the Algonquin word for chieftain, the head of the tribe. In 1905 Roosevelt decided to expand the house, adding the largest room, called the "North Room", for $19,000 (equal to $498,715 today). The home now has twenty-three rooms.

The house and its surrounding farmland became the primary residence of Theodore and Edith Roosevelt for the rest of their lives. Sagamore Hill took on its greatest importance when it became known as the "Summer White House" during the seven summers (1902–1908) Roosevelt spent there as President. Roosevelt died at Sagamore Hill in January 1919.

On July 25, 1962, Congress established Sagamore Hill National Historic Site to preserve the house as a unit of the National Park Service. As with all historic areas administered by the National Park Service, Sagamore Hill was listed on the National Register of Historic Places on October 15, 1966. The home is normally open to the public by guided tour after rennovations lasting through 2015.

LARRY PERSONAL NOTE: IT TOOK THREE ATTEMPTS OVER SEVERAL YEARS TO FINALLY GET TO THIS PLACE -- AND THEN I HAD TO PARK ILLEGALLY FOR A COUPLE OF MOMENTS TO GET THE PHOTOS