The present Town of Hamilton was once occupied by several native tribes. European settlers arrived in the 1730s. In 1768, George and Tabitha Roach Tavenner built the first house in the Hamilton area. Their son, Richard and his wife Ann Hatcher, built an estate called Harmony and the surrounding area was thereafter known as Harmony.
The Leesburg and Snickers Gap Turnpike Company opened a road connecting Leesburg and Snickersville in 1831. Growth ensued and by 1833, the area had enough population to sustain Harmony Methodist Church, which was built on land donated by Richard and Ann Hatcher Tavenner. The town also became known as Hamilton Store after a store founded there by Charles Bennett Hamilton. In 1835, John Quincy Adams approved a post office located in Hamilton's store and the town's name was recorded as Hamilton.
The last important Civil War action in Loudoun County, known as The Harmony Skirmish, took place on March 21, 1865 as confederate Colonel John S. Mosby and his troops surprised troops commanded by Colonel Marcus Reno.
By 1868, a steam railroad from Alexandria had come to Hamilton along the future route of the Washington and Old Dominion Railroad. Many tourists came to the town seeking relief from the city's heat. There was a one and 1/2 mile boardwalk that traversed the town and a dance hall. By 1900, the Town of Hamilton was Loudoun County's second largest town. The booming businesses in Hamilton included two newspapers, a butcher shop, a men's clothing store, a broom factory, a milliner, a dentist, two hardware stores, a stove shop, a flat racecourse, a livery stable and boarding houses.
The advent of the automobile led to a slow decline in tourism. In 1926, many of the town's central businesses were destroyed by fire and tourism thereafter declined sharply. Hamilton has since been known more as a residential community.