After the onset of the American Civil War, and with a strategic location overlooking the city, the Meridian Hill estate and mansion, along with the land of neighboring Columbian College (founded 1821, later moving and becoming George Washington University), were taken for use as an army encampment named Camp Cameron.

At that time, Washington was experiencing postwar growth and some prosperity, so in 1867 the old Porter estate's land was subdivided into smaller lots.

She put forward, without success, two ambitious proposals, one by architect Paul J. Pelz in 1898 and the second by Franklin W. Smith in 1900, both with designs to construct a colossal presidential mansion on Meridian Hill to replace the White House.

In 1901, the Senate Park Commission (with its McMillan Plan) undertook a set of formal changes to Washington's civic appearance, most famously by reconfiguring the city's National Mall.

The commission also decided, with Mary's input, that a park on Meridian Hill was appropriate, and proceeded to plan for its creation.

Later, throughout the many years of park construction, she lobbied Congress to maintain the flow of funding necessary to complete the project.

This construction technique for the park was created by master craftsman John Joseph Earley; he and his team of skilled artisans worked for years on the project.

Another interesting fact is the use of the park as a filming location for an OSS movie, where the Joan of Arc as well as the Dante statue can be seen.

[12][13][14] After 1970, with inner-city areas of Washington experiencing an economic decline, the park and its neighborhood suffered some decay for a number of years, with crime and vandalism becoming a problem.

On Sunday afternoons during warm weather, people gather from 3 to 9 p.m. in the upper park to dance and participate in a drum circle.

The actual planting scheme was designed by New York landscape architects Vitale, Brinckerhoff, and Geiffert.

In the past, gardens of this scope generally were reserved for aristocrats, but Meridian Hill Park, a product of democracy, was made for all people.