Only three families remain as permanent residents, while the remainder of the site is open to visitors who wish to learn of its history or to simply enjoy the forested surroundings.

It was added to the National Register of Historic Places on June 6, 1980 for its significance in agriculture, archaeology, commerce, education, industry and community planning.

By 1844, the production of his mill could not grow fast enough to meet the demands of the merchants he supplied, so Felt began to look for land in New Jersey on which to build a second factory.

After the place was again deserted, the Union Country Park Commission bought it and included it in the Watchung Reservation, renting the houses to families.

Since many of the main structures are no longer standing, an ongoing preservation effort aims to show visitors how the inhabitants of Feltville-Glenside Park once lived.

Grassmann was a lifelong Elizabeth resident who made his fortune in land surveying and kaolin processing; the trust that bears his name is still in existence today.

"[8] It was Grassmann who apparently persuaded celebrated Nicaraguan/Mexican artist Roberto de la Selva to paint themed murals throughout the first floor interior of the Mexican Cottage.

In the late 1920s, during his first trip to the United States, de la Selva spent months in rural Union County painting the murals, which depict native Mexicans at work, play and worship, including statues of both ancient gods and the Virgin Mary.