It is the oldest extant house in Manhattan, having been built in 1765 by British military officer Roger Morris, and was also home to the family of socialite Eliza Jumel in the 19th century.

Continental Army General George Washington used the mansion as his temporary headquarters for one month in late 1776, during the American Revolutionary War, after which British and Hessian officers occupied the house until 1783.

[25] In the late 19th century, the house was visible from several miles away and had views of most locations in Manhattan, despite being readily accessible from the elevated Ninth Avenue Line.

[35] The northeast corner of the park contains a sunken garden,[36][37] which was designed by Helen Elise Bullard during a 1934–1935 Works Progress Administration renovation.

[48] At the time, Roger and Mary Morris lived at Broadway and Stone Street near the site of the present Bowling Green Custom House.

[51] Roger Morris described the site as a place where he "might find an eligible retreat for a gentleman fond of rural employments and who wishes to pass the Summer months with pleasure and profit".

[52][61][62] The historian William Henry Shelton wrote that Mount Morris was vulnerable to arson attacks from Patriots—who sought American independence—since Roger was a member of New York's legislative council.

[6][63] Continental Army general William Heath and his officers occupied the house as early as September 5, 1776, holding it for their commander in chief, George Washington.

[77] Washington retreated around October 21–22 to flee advancing British troops,[66][78][79] and Continental Army colonel Robert Magaw was left to guard the house.

[96] One observer was quoted in the New York Times as saying that the mansion was suitable for both temporary and permanent visitors and characterized the house's octagonal parlor room as being "very happily calculated for a turtle party".

[116][117][g] The Jumels had largely been "neglected by society" when they lived in Lower Manhattan, and Eliza, who had come from poor beginnings, was anxious to become part of New York City's elite.

[95] At some point in the late 19th century, either right before or not long after Eliza Jumel's death, a flagstone carriage drive was added in front of the mansion.

[171][j] Elizabeth's husband, the early filmmaker Louis Le Prince, wished to screen his films publicly at the mansion but disappeared mysteriously in 1890.

[197] Seth M. Milliken moved to foreclose on a $30,000 mortgage on the house in May 1902,[198] and a lis pendens was filed against the mansion early the next year as part of the foreclosure proceedings.

[199] The Daughters of the American Revolution formed a committee in February 1903 to raise money for the mansion,[200] and the Board of Estimate and Apportionment approved the park's creation that May.

[209] Their sister organization, the Sons of the American Revolution, submitted a competing bid to operate the museum[210] but later agreed to provide financial support to the Daughters.

The association planned to restore the original Colonial-style architectural details, unseal the old fireplaces, display some of the Jumel and Earle families' furniture, and landscape the gardens around the house.

[35][275] By the end of the 20th century, the mansion and surrounding area were frequented by buses carrying European and Japanese tourists, prompting complaints from local residents.

The museum had been planning a $350,000 renovation at the time, and its executive director Carol Ward wanted to sell the Olive Branch Petition manuscript to raise money for an endowment.

The New York Times described the house in late 2023 as being in such poor condition "that it is possible to touch it and walk away with a moist, splintered clump of wood siding in the palm of your hand".

[277][278] When the museum first opened, the New-York Tribune described the collection as having a Thomas Sheraton sofa with carved legs; pewter lamps and tankards; hand-carved four-poster bed frames; and a 19th-century woman's calash that resembled "a cross between a bagpipe and a flatboat".

[315] According to a 1921 Christian Science Monitor article, the museum exhibited various late-18th-century relics such as coins, guns, prints, clothing, china, furniture, and a Bible belonging to Washington.

[317] The museum also displayed clothing and artifacts belonging to Eliza Jumel,[316] as well as the collections of Reginald Pelham Bolton and William Lanier Washington.

[231] In its early years, the museum also presented events such as lectures on the house's history;[334] receptions hosted by the Washington Headquarters Association;[234] and meetings of the WHA[335] and the Daughters of the American Revolution.

[362] Josiah Collins Pumpelly wrote in 1903 that the house "still remains a conspicuous monument of the taste and ambitious aspirations of those who lived during the infancy of the Commonwealth".

[91] A writer for The Spur said in 1936 that "the visitor sees not merely a building but a structure warm with memories of New York's dear dead days",[364] and a critic for the Christian Science Monitor said in 1945 that the house stood "four-square and benevolent in the mellow gold of autumn".

[371] A writer for Insider wrote in 2022 that, despite the presence of a modern Ring doorbell at the entrance, walking into the house "felt like stepping back in time".

[373] The mansion was also documented as part of the Historic American Buildings Survey in the 1930s,[374] and the New York State Education Department erected two signs outside the house in 1935, summarizing the structure's history.

[384] Later in the century, Fitz-Greene Halleck wrote his lines on the Greek patriot Marco Bozzaris on a rocky outcrop near the mansion overlooking the Harlem River.

For example, it was featured in New-York Historical Society's 1952 exhibition of pre–Civil War houses in New York City,[392] and artifacts from the mansion were displayed in the lobby of 1095 Avenue of the Americas in 1979.