Hirvensalmi is a municipality and town in the South Savo (South Savonia) region of Finland. It is characterised by numerous lakes and extensive forests, with Lake Puula and Lake Suontee as its principal lakes; Puula is noted for the clarity of its water and has 19 maintained landing sites with campfire spots and restrooms. The Puukonsaari ferry gives access to the Puula archipelago for visitors without their own boat.
The municipality is reached by road: regional road 431 connects it with Mikkeli to the east and Leivonmäki to the west, while regional road 429 approaches from the south off highway 5, the route from Helsinki and Lahti. Buses also run from Mikkeli. Neighbouring municipalities are Joutsa, Kangasniemi, Mäntyharju and Pertunmaa.
Notable sites include Hirvensalmi Church, a grey stone cruciform church built in 1915 whose bell tower dates to 1783, and the Kissakoski factory area, a historic industrial environment with notable architecture that now houses a cafe-restaurant and local businesses. In the village centre, Tervaleppäkuja (Alder Avenue) is described as Finland's only black alder avenue, with more than 100 trees over 100 years old and over 30 metres tall. The Hahlavuori rock paintings, depicting human and elk figures, are accessible by boat. Outdoor activities include cycling, paddling, fishing, hiking and berry picking, and the Satulinna hotel, a manor, is known as the venue of the reality series Vain elämää.