Muonio is a municipality of Finland. The town is located in far northern Finland above the Arctic Circle on the country's western border, within the area of the former Lappi (Lapland) province. The municipality has a population of 2,325 and covers an area of 2,039.97 square kilometres (787.64 sq mi) of which 133.91 km2 (51.70 sq mi) is water. The population density is 1.22 inhabitants per square kilometre (3.2/sq mi).

Lapland is the largest and northernmost region of Finland. The 21 municipalities in the region cooperate in a Regional Council. Lapland borders the region of North Ostrobothnia in the south. It also borders the Gulf of Bothnia, Norrbotten County in Sweden, Finnmark County and Troms County in Norway, and Murmansk Oblast and the Republic of Karelia in Russia. Topography varies from vast mires and forests of the South to fells in the North. The Arctic Circle crosses Lapland, so polar phenomena such as the midnight sun and polar night can be viewed in Lapland.