Designated a cemetery from 1841 to 1842, burials at Marsland Hill included Charles Armitage Brown whose memorial is located on the slope behind St Mary’s Cathedral, after being rediscovered by local historians in 1921 following an extensive search. The cemetery was officially closed in 1908.

In 1855, the top of the hill was levelled, reducing its height by some 12m to create the headquarters for the imperial regiments stationed in Taranaki. Between 1874 and 1880, the barracks provided temporary accommodation for newly arrived settlers, and in 1891 the remaining section was relocated to Mt Taranaki as tourist accommodation, where it is now known as The Camphouse.

In 1909 Governor General Lord Plunket unveiled the New Zealand Wars Monument, and the South African War Memorial followed in 1911, unveiled by Governor General Lord Islington in memory of the Taranaki men who fell in the Anglo-Boer War.

The Observatory was opened in 1920, following the formation of a local Astronomical Society. The building has expanded from the original 1920 dome with additions in 1936 and extensions for a second telescope in the 1970s.

A 37 bell Carillon donated by George Kibby in memory of his late wife Mable was installed in 1971. It received a major refurbishment in early 2014. Together the brass bells weigh over four tonne and play daily at 10am, noon, 2pm, and 4pm.

The surrounding reserve has grown over the decades to now encompass 3.78 hectares, which were declared a historic reserve in 1987. The reserve has many recreational uses and with its great views over the city is a popular picnic, heritage, and lunchtime running destination.