This is a full-scale landscape garden that was created around 1898 as a villa for one of the city's wealthiest merchants. In 2001, the garden was designated as a "place of scenic beauty" under the Law for Protection of Cultural Properties, and is the only nationally designated cultural property garden in Hokkaido.

Miharu Park, located on a hill near the Yunokawa hot spring resort area, includes Kosetsuen, a landscape garden created in the 1890s by the Iwafune family, one of the city's wealthiest merchants, as their summer home.

The park is dotted with cherry trees, including Someiyoshino, and the lawn area, which is often used as a field trip site, is surrounded by flowers in full bloom in spring. In summer, fireflies fly around the clear stream and cicadas can be seen hatching. In addition, the brick greenhouse and the shoin-style garden pavilion, which is decorated in the style of a tea ceremony house, provide a place to relax and enjoy many other attractions.

In the fall, the garden is transformed into a scenic spot famous for its autumn foliage, which attracts many visitors. Since 2009, the Hakodate Momi-G Festa, an event to illuminate the autumn leaves at night, has been held here.

The "Green Center," which can be used as a rest area, is equipped with a terminal that allows visitors to search for trees and birds in the park, as well as books. Free Wi-Fi is also available. There are several restrooms in the large park, but the multipurpose restroom is located in the Green Center.