This three-day weekend offers the annual celebration of the Declaration of Independence with all the appropriate fireworks, food and good times. However, during this sesquicentennial of the Civil War, there are also events scheduled during the same time period to commemorate the war. These include the opening a major new portrait exhibit, the annual reenactment of the Battle of Gettysburg and the 150th anniversary of the Battle of Monocacy in Frederick, Md.

Grant and Lee: The National Portrait Gallery in Washington debuts its newest Civil War-related exhibit, “One Life: Grant and Lee, 1864-1865,” on July 4, from 10 a.m. to 8 p.m. According to the gallery: “This special installation … considers two lives that were intertwined during the Civil War. Grant and Lee both stand alone as genuine world historical individuals in their impact on the America, but they are also the product of their relationship to each other.”

The exhibit, which closes May 25, 2015, is housed in a building that served as a barracks and hospital for Union soldiers. It was also the site of President Abraham Lincoln’s second inaugural ball on March 6, 1865.

Ron Musick, of Chicago, left, sits near Union reenactors as they pretend to be the victims of a battle as they pose for photos following a march to mark the anniversary of Pickett’s Charge at Gettysburg National Military Park on July 3, 2013. This year’s reenactment will mark the 151st anniversary of the Battle of Gettysburg. (Matt McClain/ The Washington Post)

Battle of Gettysburg: From July 4 to 6, the annual reenactment of the 1863 Battle of Gettysburg takes place just outside the Pennsylvania town, with daily battles of pyrotechnics, living history exhibits, period music and a dance on Saturday night. The grounds will be open from 8:30 a.m. to 6 p.m. on July 4 and 5, and on July 6, the hours are 8:30 a.m. to 3:30 p.m.

Admission to the reenactment events for adults costs $29 for one day, $49 for two days and $69 for three days. For children ages 6 to 12, a one-day ticket is $16, two days is $24 and three days is $29. Children under six get in free.

Battle of Monocacy: The 150th anniversary of the Battle of Monocacy at the Monocacy National Battlefield  in Frederick, Md., will be commemorated from July 5 to 11, with a special museum exhibit, “Honoring Heroism,” featuring the Civil War maps of Jedediah Hotchkiss. Plans also call for a living history encampment, military demonstrations, battlefield hikes, programs and concerts. The hours for this free event are 8:30 a.m. to 5 p.m. every day.