Ruokolahti is a municipality situated in the region of South Karelia on the south-eastern border of Finland. Ruokolahti covers a larger area than any other municipality in the Province of Southern Finland. Ruokolahti has some 5,250 permanent inhabitants. More than 3,000 summer homes occupy the shores of Ruokolahti's numerous lakes.
The history of Ruokolahti dates back to the 16th century, when the Governor of Vyborg ordered a new parish to be established on the shores of southern Lake Saimaa. This parish was named Ruokolahti. During subsequent centuries, the area of Ruokolahti was within the demarcation zone on many occasions, and the municipality obtained its current form at the end of the 1940s, when the present town of Imatra was established from the industrialised parts of Ruokolahti.
The easy-going Karelian lifestyle is still prevalent in the area. The Imatra border station, situated only 20 kilometres from Ruokolahti, provides a route to Vyborg and St Petersburg in Russia.