In the 1780s, southwestern Pennsylvania was part of the frontier, and Washington County contained about 42 forts, according to estimates by the county's historical society.

This weekend, visitors can learn about life back then when the Washington County Historical Society holds a free open house at its Frontier History Center in Washington Park.

Set to coincide with the city of Washington's bicentennial celebration, the event will include the Civil War re-enactment group that was seen in the film "Gettysburg," which will shoot cannons several times throughout the day Saturday in the grassy area near the First Presbyterian Church, along College Street.

About 40 re-enactors will take part in the annual Whiskey Rebellion Festival from 11 a.m. to 6 p.m. Saturday in front of the David Bradford House.

Living history interpreters dressed in period clothing will explain how the earliest settlers coped with the harsh realities of everyday life.

"Initial housing for the first arrivals was basically nothing more than lean-tos built into the hillsides," said Clay Kilgore, society curator, explained how . "Log cabins came along later."

To battle the Indians, two or three families would band together and build simple block houses with small portals through which they could fire muskets. As time progressed, larger groups of families would construct more elaborate stockades or forts in a central location, where they could meet to defend themselves when they got word of an upcoming battle. By the 1790s, however, the need for the forts had eased because most of the Indians had left the area.

"The society's Frontier History Center is built to resemble one of these early settler forts, not to be mistaken for military forts built for an army," Mr. Kilgore said. "Ours consists of a stockade and blockhouse with an interior cabin and lean-to and a small, single-story settler's cabin and open face camp outside."

Visitors will be able to enter structures and see primitive furnishings, such as benches, tables and cooking equipment.

Ron Malmgren of Washington plans to show his collection of 18th century weapons, chiefly a variety of muskets that were used on the frontier. Throughout the day, living history interpreters will stage military drills in which visiting children can participate. Society member Bill Schuster will conduct basic woodworking demonstrations.

The Frontier History Center is considered a work in progress, and plans are being considered to build a trading post and meeting house on the site.

A parade down Main Street will kick off the weekend at 10 a.m. Saturday.

From 11 a.m. to 5 p.m. Saturday, the LeMoyne House, home of the historical society, will be open for free tours that will feature Civil War re-enactors. The nearby David Bradford House also will offer free tours and cooking demonstrations then.

A free shuttle will pick up visitors throughout the day at the Bradford and LeMoyne houses and transport them to the Frontier History Center, where they'll be greeted by a "frontiersman," who will share some history.

Details: 724-225-6740.

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