This park was added to the National Park Service official roster a the end of 2022, increasing the number of sites to 424.

There is very little information about the site as it does not yet even have its own web page within the nps.gov domain. Here is what is written about it:

New Philadelphia was the first known town planned and legally registered by an African American before the Civil War. Frank McWorter, a formerly enslaved man from Kentucky, founded the town in 1836 and bought his freedom and the freedom of 15 family members. The rural community situated near the Mississippi and Illinois Rivers flourished at first, but later declined when the railroad bypassed the community in 1869. The community dissolved in 1885. By the 1940s, nothing of the town remained above ground. New Philadelphia disappeared as plows turned over the soil and buried any material remains left behind. Today, historical documents, oral histories from town descendants and community members, and artifacts keep the town's story alive.

...Excerpt from NPS website