His blue Union army cap fell down over his ears, but 10-year-old David Kriesberg was determined to wear it. With Civil War reenactors demonstrating cannon fire nearby, David was afraid that his father would get carried away if he had the cap.

"If he wore it, he'll act like a real guy," David explained, saying his father, Caleb, is such a Civil War buff that he was apt to do something embarrassing. "I didn't want to take the risk."

The Kriesbergs, of Silver Spring, were among more than 150 people, onlookers and reenactors, who turned out yesterday at Fort Stevens, where 140 years ago this weekend Union forces fended off a Confederate offensive in the only Civil War battle fought within the District.

Sponsored by Rock Creek Park, which now runs the Northwest Washington fort, the commemoration included model encampments, dramatic presentations, an Abraham Lincoln impersonator and a performance by the Wildcat Regiment Band.

The original clash stretched from Fort Stevens into the Silver Spring area, which at the time was mostly farmland and woods. Records show that the fighting resulted in 800 casualties on both sides, including 40 Union soldiers buried at nearby Battleground National Cemetery.

Though the cannons were reproductions and the Confederate troops did not show up, the battlefield garb and campsites yesterday were evocative of the actual event.

A group from Fauquier County portrayed Union soldiers. In their blue wool pants, flannel jackets and Union Army caps, they sweated under the weight of artillery supplies tied around their bodies. The Wildcat band, modeled after a band used to recruit Union soldiers, played instruments from the 1860s.

It was all part of an effort to make history accessible, said John Favors, a reenactor who led the cannon demonstration.

"Too many times they see things in museums, behind a piece of glass," he said. "The best way to learn history is to live it."

The Union soldiers included Matthew Devor and a son, Marshall, 16, of Front Royal. Marshall participates in about a dozen reenactments a year. Matthew Devor said he started about a year ago, at the urging of his son, who hopes to teach American history.

Taking part in the activities fosters an even deeper fascination with history, Matthew Devor said. "If you have any curiosity whatsoever, you can't help it," he said.

Stratton Shartel, 43, a lawyer from Springfield, had one of the most popular roles. Posing as Abraham Lincoln, in knee-length black coat, top hat and beard, he drew the attention of many children. Some asked him how he could still be alive.

"I never died," was Shartel's standard answer.

The real Lincoln came to the fort July 12, 1864, to watch the battle, and a placard marks the place where he stood. Lincoln was nearly seven feet tall in his top hat, and according to legend, he was nearly hit by a Confederate sharpshooter before Capt. Oliver Wendell Holmes Jr., the eventual Supreme Court justice, yelled, "Get down, you fool!"

Shartel said he has been a Lincoln fan since his father took him to Ford's Theatre when he was 8. For seven years, he has led tours at the place where Lincoln was assassinated and has dressed as Lincoln for classroom visits and Civil War commemorations.

Although most visitors wore modern clothes, Elizabeth McClung, 38, and her husband, Stuart, 51, strolled the fort in 1860s civilian garb. She wore a corset and a petticoat she had made and carried a parasol in her white-gloved hands. He wore a gray suit.

Although they live in Hagerstown, Md., the McClungs belong to the 21st Georgia Volunteer Infantry Company A, a Confederate unit that Stuart commands. Elizabeth McClung often portrays civilians, but she recently began playing female soldiers who dressed as men.

The McClungs joked that they were afraid to show up in Confederate battle gear.

"We're on enemy territory," Stuart McClung explained.

Civil War reenactors mark the 140th anniversary of the Battle of Fort Stevens with an artillery demonstration. Margaret Brown, 6, is greeted by Stratton Shartel, portraying Abraham Lincoln, who observed the only Civil War battle to take place in the District.