In 1910 the land of Kumla manor was sold and divided into lots. During the 1920s to 1930s there was a lot of summer cottage development in that area. From 1950s and onwards the cottages began to be converted into permanent dwellings in a large scale. Trollbäcken housed the municipal executive board of Tyresö from 1940s until the Bollmora centre was built.
Trollbäcken has as of January 1, 2004 11,715 inhabitants, which is 29.2% of the population of Tyresö Municipality.
Lake Barnsjön is a popular spot for bathing and fishing.