Pontypool Park House was gradually extended and modified, with major changes being carried out in the mid-18th century, the early 1800s and 1872. Alterations were also made within Pontypool Park during the 19th century and included the dismantling of the old ironworks in 1831, the reconstruction of the park gates by Thomas Deakin of Blaenavon in 1835, the planting of trees to increase the privacy of the family from the gaze of outsiders, and the development of the American Gardens in 1851.