The municipality has a population of 343 (31 August 2013) and covers an area of 860.38 square kilometres (332.19 sq mi) of which 761.12 km2 (293.87 sq mi) is water. The population density is 3.46 inhabitants per square kilometre (9.0 /sq mi).
89.2% of the population is Swedish-speaking, 6.1% is Finnish-speaking, and 4.7% speak other languages.
The first visitors to Kumlinge were Vikings who stopped there during their voyages. The first permanent residents arrived in the 13th century. According to taxrolls from the 16th century there were about a dozen houses on the main island at the time, home to mostly farmers and fishermen. In the 20th century the population of Kumlinge slowly began to decline.
The church in the village is dedicated to St. Anne and dates from the 15th century. There are two farm museums in Kumlinge: Hermas museigård and Sjölunds gårdsmuseum. There is also a memorial stone in Fälberget which is dedicated to the war of 1808 when a Russian battalion was defeated in the village of Kumlinge. The old post route also goes through Kumlinge.