The British occupation forces elevated the province to the State of Schleswig-Holstein in 1946. For one and a half years (1949-1951) Groß-Hansdorf-Schmalenbeck formed a part of Ahrensburg collective municipality, before it regained municipal status, under the now official name Großhansdorf since. The inhabitants spread over the locality Schmalenbeck (c. 60%) and the locality Großhansdorf (unofficially: Alt-Großhansdorf; c. 40%). Following the massive destructions by Bombing of Hamburg in World War II many a homeless Hamburger moved to Großhansdorf.