Washington is an unincorporated community in Adams County, Mississippi, United States. Located along the lower Mississippi, 6 miles (9.7 km) east of Natchez, it was the second and longest-serving capital of the Mississippi Territory.

This area along the Mississippi had long been inhabited by indigenous peoples. At the time of European encounter, the Natchez people controlled much of the area. They were descendants of the earlier Mississippian culture that had built earthwork mounds. European Americans, settling the area after the American Revolution, named the town for George Washington. Some of the original settlers of the area were Colonel Andrew Ellicott, Joseph Calvit, and John Foster. The townsite was established near a water source known as Ellicot's Spring.

Washington became the second territorial capital, when the seat of the Mississippi Territory General Assembly was moved from Natchez to Washington on February 1, 1802. Fort Dearborn, located at Washington, was for a time the largest military installation then extant in the United States, with more than 2,000 soldiers stationed there, including such notables as Brigadier General Leonard Covington and future General Winfield Scott. It was established in 1802 to protect the newly relocated capital of the Mississippi Territory. Two slaves were convicted of the murder of Thomas H. Green, son of Abner Green, and executed April 23, 1810, at Washington, Mississippi Territory.

The community, and nearby Woodville, both made public gestures in support of the Monroe administration during the lead-up to what became the War of 1812. As of 1813, celebrations might be held at DeFrance's Hotel. According to a history of Methodism in Mississippi, the church at Washington "became the most popular preaching place in all the country. The congregations were large and appreciative, many of whom, from time to time, were sweetly drawn into the gospel net...The social meetings of the Church were highly appreciated and well attended...Washington was now in the zenith of its glory and prosperity." Surnames of white families that lived in or near Washington were Bowie, Calvit, Chew, Covington, Dangerfield, Freeland, Grayson, Magruder, Wilkinson, Winston, and Wailes. According to a 1906 survey of "lost villages of Mississippi":

It was a gay and fashionable place, compactly built for a mile or more from east to west, while every hill in the neighborhood was occupied by some gentleman's chauteau. The presence of the military had its influence on society; punctilio and ceremony, parades and public entertainments were the features of the place. It was, of course, the haunt of politicians and office seekers; the center of political intrigue, the point to which all persons in pursuit of land or occupation first came. It was famous for its wine parties and its dinners, usually enlivened by one or more duels immediately afterward.

The town had one Main Street (the Natchez Trace) that ran for about a mile. The Mississippi constitution convention of 1817 met in Washington at the Methodist Meeting House (which was purchased by Jefferson College in 1830). Mississippi's first constitution was written and adopted here, and the state's first legislature convened here in 1817. The preliminary trial of U.S. vice-president Aaron Burr occurred under some nearby oak trees. After Mississippi was admitted to the union in 1817, the legislature met once in Washington, and afterward in Natchez. In the late 1810s there was a yellow fever outbreak in the town, which had previously been considered a "salubrious climate" compared to Natchez, and the disease killed "a number of the best citizens, so that people were restrained from fixing their family residences there." The capital was officially moved to Jackson in 1822, in keeping with the Act passed by the Assembly on November 28, 1821, which chose to have a more central location for better accessibility to more residents. The Natchez Trace fell out of use as a U.S. post road by 1824, consequent to the development of the steamboat, and "from this date (1825–26) a variety of natural causes contributed to its depopulation until for a score of years it has been nothing more than a scattered village." An outbreak of yellow fever in 1825 killed 52 of the approximately 250 residents of the town.

By the 1840s the "old village" already represented a "forgotten society."

The old Methodist Meeting House building was demolished by a tornado in January 1873.