Olney Inn, a historic dining spot on Georgia Avenue in the Maryland suburbs of Washington, has been sold to a developer. The restaurant will continue under new management, but its once-spacious foregrounds will be occupied by a Williamsburg-style shopping arcade and parking lot.

Robert N. Wolpe of Washington has purchased the building and approximately five acres from Harry Simms for a sum reported to be between $1 million and $1.2 million. The antiques barn adjacent to the inn is expected to continue operations. The new 35,000-square-foot colonial arcade will feature boutiques.

Wolpe, in turn, has leased the main premises and sold the restaurant business to Herbert and Gerry Kaufman of Hillandale. The Kaufmans, a public accountant and a dance instructor, admit they have no restaurant experience, but say they are determined to bring the inn back to "the way it was when we were dating." That means serving continental food in the main dining room and providing concert music at dinner.

The farmhouse in Olney dates from 1835, although it did not become an inn until 1926. It was founded by Clara May Downey, who had a flat tire on the premises and ended up falling in love with the house. She started a tea room there and entertained proper ladies with English maids.

The most famous guest was President Franklin D. Roosevelt. The ramp built for his wheelchair still remains. More recently, the inn became a fashionable place for Sunday brunch and theater suppers.