Falster is an island in south-eastern Denmark with an area of 486.2 km2 (187.7 sq mi) and 43,398 inhabitants as of 1 January 2010. Located in the Kattegat, Belts and Sound area, it is part of Region Zealand and is administered by Guldborgsund Municipality. Falster includes Denmark's southernmost point, Gedser Odde, near Gedser.

Guldborgsund Municipality is a kommune in the Region Sjælland of Denmark, created on 1 January 2007 from six (6) former municipalities on the two islands Lolland in the west and Falster in the east bordering the Guldborgsund strait. It covers an area of 903.15 km2 (2013) and has a total population of 60,231. Its neighboring municipalities are Lolland to the west and Vordingborg to the north. Its administrative seat is in the town of Nykøbing Falster. Its mayor as of 1 January 2022 is Simon Hansen, representing the Social Democrats.