The National Park Service will celebrate the 250th anniversary of George Washington's birth Saturday by closing portions of the George Washington Memorial Parkway near Mount Vernon for a parade and a 10-mile footrace.

The two-hour, 45-unit parade, with high school bands and marching units from across the nation, will march from Fort Hunt to Mount Vernon beginning at 11:30 a.m.

A concert with bands representing the original 13 colonies will be held at 2 p.m. inside Mount Vernon. The cost is $3 for adults and $1.50 for children.

An expected 3,000 runners will compete in the Mount Vernon Classic footrace, which begins at 8 a.m., and will run along the parkway from Mount Vernon to the George Washington Masonic National Memorial Temple in Alexandria.

Registration, limited to 3,000 runners, will be accepted until Friday night at the Old Town Holiday Inn in Alexandria. The entry fee is $7. Further information is available from race organizer John Sullivan at 931-4597, evenings.

The parkway between the city and Mount Vernon will be closed from 7:30 to 10 a.m. for the race, and the section south of Waynewood Boulevard will remain closed until 3 p.m. for the parade. In addition, a book fair will be held at Fort Hunt from 10 a.m. to 4 p.m. and an arts and crafts exhibit from 1 to 4 p.m.

English double-decker buses will provide free shuttle bus rides along the parade route from Fort Hunt and several nearby schools and churches, but the Park Service is encouraging spectators to come by bicycle and on foot on the paved bike trail along the parkway.

The shuttle buses will run continuously from 10 a.m. to 3:45 p.m. along the parade route and to free parking areas at Fort Hunt, accessible from Old Fort Hunt Road, Fort Hunt High School on Fort Hunt Road, Waynewood School on Waynewood Boulevard, and the Good Shepherd Church on Mount Vernon Highway (Rte. 235).