The City of Baltimore built Palladian pavilions connected by hyphens on either side in 1910 as a concealed public toilets structure,[5] but these do not reflect historical construction that were originally on the estate.

[5] A circa 1912 stable,[6] once used to house the horses of the city's park rangers, has been restored and is now used for classroom space as well as a rental facility for events and meetings.

Charles Carroll the Barrister, (1723-1783), began building the present 2+1⁄2-story Georgian style central block, incorporating his brother John's kitchen and flanking it with a wash house and an orangery.

[5] After Barrister Charles' death in 1783, his widow made further changes, connecting the outbuildings and adding a greenhouse to the orangery and expanding the laundry, resulting in a complex about 360 feet long.

The forming by several businessmen and industrialists, after hearing details of the incredible new transportation technology now being used in Great Britain from several of its leading merchants, the Baltimore and Ohio Railroad Company, was formed in 1827 which included Charles Carroll of Carrollton, (1737–1832), as one of its directors and the important ceremonial position of setting the First Stone for the railroad at the end of the big parade, festivities and ceremonies on Independence Day, July 4, 1828, near the old house.

Attracted to the growing industrial capabilities of the area were industrialists, inventors, manufacturers such as Peter Cooper (1791–1883) of New York, who designed the first steam engine locomotives for the railroad when it quickly shifted from the horse-drawn power used during its first four years.

Hundreds of workers with specialized industrial skills, both citizens and recent immigrants, worked in southwest Baltimore and lived in the surrounding streets and communities.

Other nearby neighborhoods were Poppleton, Union Square, and East Baltimore, along with the earlier Pigtown, (also known by the gentrified 1980's as Washington Village).

[5] Beginning in January 2012, a collaborative operating agreement between the City of Baltimore's Department of Recreation and Parks and the B&O Railroad Museum and The National Society of The Colonial Dames of America (Maryland Chapter) (a descendants' heritage group.