Maryland residents can choose from two local fairs Sunday, as Gaithersburg celebrates Olde Towne Gaithersburg Day, and Montgomery County holds the Ethnic Heritage Festival at Wheaton Regional Park.

The theme of this year's Olde Towne Gaithersburg Day is "200 Years of the Constitution, Then and Now."

Officials expect 45,000 people, nearly double what the festival attracted when it began in 1982.

"The fair has grown to almost a year-round project for me," said Janet Gonchar, recreation supervisor for Gaithersburg's Parks and Recreation Department.

"We wanted an event that would attract people to Gaithersburg. Not many people know about our historic area."

Indeed, for people who think of Gaithersburg as a newly developed suburb of Washington, it will be a surprise to know that the settlement, first known as Log Town, began in 1765 and the town officially became Gaithersburg in 1873 when the Baltimore & Ohio railroad completed a stop there.

The name was in honor of a prominent citizen, Benjamin Gaithers, and his family.

The day's festivities will include performances of bluegrass, instrumental and choral music, wagon rides through Gaithersburg's historic district and historic house tours, a Civil War encampment reenactment, carnival rides, arts and crafts displays, and food vendors.

Also featured will be rides on a passenger train from the historic Gaithersburg train station to Dickerson and back. The train is pulled by a vintage diesel locomotive.

Admission to the Olde Towne fair, which will be held from 11 a.m. to 5 p.m. in the downtown area and the City Hall grounds, is free, although tickets must be purchased for the train ride.

A rain date is set for Sept. 27.

For further information, call Gonchar at 926-1100 or 926-1131.

Competing for residents' attention will be the Ethnic Heritage Festival.

Scheduled for noon to 7 p.m. Sunday, the festival will be a celebration of more than 40 cultures.

"We wanted to celebrate the positive aspects of diversity in Montgomery County," said Lisa Mandel-Trupp, chairwoman of the Ethnic Festival Planning Committee.

Besides food vendors and arts and crafts displays, the attractions will include hot-air balloon rides, glass blowing and scarecrow making.

From two stages, music and dancing demonstrations will be given by Burmese, German and Irish performers, among others.

Children and adults in ethnic dress will parade through the park at 2:15 p.m.

Admission is free.

For more information about the fair, call 279-1969.