By Gary Robertson

RICHMOND, Virginia (Reuters) - Virginia's Natural Bridge, a soaring landmark bearing George Washington's initials and once owned by Thomas Jefferson, has been sold to a conservation group, a real estate firm said on Thursday.

One of the oldest U.S. tourist attractions, the 215-foot-high (65.5-meter-high) limestone feature in western Virginia was purchased by the Virginia Conservation Legacy Fund, which said it would eventually turn it over to the state park system.

The sale by Washington real estate developer Angelo Puglisi, who has owned the site since 1988, includes a 150-room hotel, caverns and 1,600 acres. Financial details were not released.

Woltz & Associates, a Roanoke, Virginia, real estate company that handled the sale, said in November that a tentative agreement on the Bridge and its surrounding properties had been reached with a non-profit conservation organization. The accord negated plans to auction off the site in December.

Under the plan, Puglisi donated the bridge and 188 of the surrounding acres, valued at about $21 million, to the Virginia Conservation Legacy Fund. The Fund purchased the remaining land and assets through a loan. Once repaid, the group plans to turn over the whole site to the Virginia state park system.

Washington, the first U.S. president, is thought to have surveyed the site as a young man. His initials are carved into the wall of the Bridge.

Jefferson, author of the Declaration of Independence and the third president, bought the property from the British crown and built a log cabin on it. It has since been in private hands.

The site was a popular destination for tourists in the 18th and 19th centuries and ranked with Niagara Falls as a must-see attraction.

The Bridge is a Virginia Historic Landmark as well as a National Historic Landmark.

(Reporting by Gary Robertson; Editing by Ian Simpson)