A young Lieutenant George Washington, while surveying the South Mountain area, reported that Middletown Valley was one of the most beautiful places he had ever seen.

[3] Later, as a colonel in 1755, he was to accompany General Braddock on the old Indian Trail that ran through the valley on his way to Fort Cumberland.

He named his property Middletown and sold the first lots there in 1767, the date officially marked as that of the town's founding.

During the Civil War, both armies passed through the town to the battles of South Mountain and Antietam.

[citation needed] Middletown preserves many historic structures indicative of its various periods of development and prosperity.

The economic prosperity experienced in the town during the first quarter of the twentieth century led to the alteration of older commercial structures and the construction of new ones in the first few blocks of Main Street, including the Beaux-Arts styled Valley Savings Bank (today the Middletown Valley Bank).

According to the United States Census Bureau, the town has a total area of 1.74 square miles (4.51 km2), all land.

The mountain itself, along with its community, Braddock Heights, is often said to be the roost of the mythical Snallygaster, a bird/dragon creature said to abduct livestock and people from the surrounding valley.

The main method of travel to and from Middletown is by road, and there are two primary highways serving the town.

U.S. Route 40 Alternate follows Main Street through Middletown, and connects eastward to Interstate 70 near Frederick and westward to Boonsboro.