Harjumägi, i.e. Harjuvärava mägi (Harju Gate Hill) is a park located on the embankment of the former Inger bastion. In 1860−1861 Komandandi tee (the Superintendent’s Road) was constructed through the bastion. The bastion was transformed to become a greenery under the management of the mayor Carl August Mayer in 1861−1862.

To have an access to the hill the staircase decorated with eight ornamental vases, called Mayer’s staircase, was constructed in 1865 at the Harju Gate. The staircase got renovated and reconstructed in 1890 and 1907. The former ceramic vases of the staircase were replaced by the cast‑iron ones in 1885−1887. In 1865 the town council leased the Harju Hill to the Gardening Society of Estonia.

In 1881−1885 the area was reconstructed and in 1887 the refurbished Harju Hill was leased on the purpose of establishing the café-summer club. After that the place became one of the most popular amusement spots for the citizens. A restaurant, bandstand, concert place together with a music pavilion and bowling were introduced. All those wooden pavilions were lushly decorated historistic buildings. All the former buildings were destroyed in 1929 and a new bandstand, which can be seen nowadays, was erected. An open‑air café was opened in 1932.

It is interesting to know, that a famous pilot Charles Leroux started his tragically ended journey on a balloon from this spot in 1889.

During the soviet times the park area was in use for different purposes. In 1980−1990 the ground in front of the bandstand hosted a music market at weekends, where one could obtain any kind of music records from all over the world. The area served also as a place for all kinds of public events and concerts (e.g. jazz).

In 2009 Võidusammas (the Victory Monument) was established at the end of the park bordering Vabaduse (Freedom) Square to commemorate the ending of Vabadussõda (the Independence War). In the course of construction works a part of the bastion embankment has been removed revealing the ancient bastion masonry. The inwards of the embankments of Harjumäe (Harju Hill) and Lindamäe (Linda’s Hill) former bastions hide numerous passages and tunnels, which can be accessed from the Kiek in de Kök museum.

The park is also uniquely known for its ancient western lime‑trees (planted in 1750) which can be seen in semicircle in front of the bandstand.

A square in front of the bandstand has undergone reconstruction in 2011, a new surfacing and the fountain were placed. This area in front of the bandstand of Harjumäe Park bears the name of the Square of 20^th August to commemorate the date of regaining the independence of Estonia (i.e. Taasiseseisvumise päev).