Smithsburg is close to the former Fort Ritchie army base and just west of the presidential retreat Camp David.

The community's development was directly influenced by factors such as migration paths, the arrival of the railroad, and advances in agricultural technology.

Smithsburg acted as a hospital town during the American Civil War in 1862, treating wounded soldiers from nearby battles at South Mountain and Antietam.

Twelve runaway slaves from Leesburg, Virginia had been seeking their way to freedom in the North when a man who considered himself to be a professional slave catcher, who had only supposed the group to be runaways, noticed the party making their way past his home at three o’clock in the morning.

Beckoning the town constable and six other men to apprehend the runaways, the supposed leader exclaimed, “Now, boys, G-d d--n you, fight!” Armed with pistols and tomahawks, the Virginia runaways had the upper hand as the rural Smithsburg men only exhibited clubs and sticks for protection.

A skirmish took place which badly wounded some of the Smithsburg men: “Constable Flora was twice knocked down, Price had his arm nearly severed and the bone broken, by a blow from a tomahawk he also had a pistol snapped in his face, which unfortunately failed to go off…Shank was several times felled to the earth, and the whole party more or less injured.”[4] Despite their efforts, only four slaves were captured - two by the Smithsburg troop and two more in an adjoining town, Leitersburg - yet the bulk of the runaways presumably were successful in their audacious escape into Pennsylvania.

During the Gettysburg Campaign, on the afternoon of July 5, 1863, Federal cavalry defended Smithsburg from an attack led by General J.E.B.

During his term, Johnson visited Smithsburg many times due to its close proximity to Camp David.

Along their route was a junkyard known as "Elwoods Auto Exchange" which the first lady felt "ruined the beautiful landscape".

She then marched up the dirt road to the main office and proceeded to give Elwoods Grimm "a piece of her mind regarding the unsightliness of the wrecking yard."

The Auto Exchange is still in operation and is now hidden by a line of pine trees which blocks its view from the main highway.

On June 9, 2022, three people were killed and a fourth was wounded in a mass shooting that occurred at Columbia Machine, Inc., previously known as Bikle Manufacturing.

[citation needed] Due to Smithsburg's location between the Appalachian Mountains and the Chesapeake Bay watershed, its climate is considered mild to moderate.

The area has warm, humid summers and winters with temperatures hovering around freezing point.