Birkholm is a small Danish island off the southern coast of Funen in Ærø Municipality. With an area of just 0.9 km² (0.3 sq mi), as of 1 January 2010 it has a population of 10. The flat, low-lying island is just over 2 km (1 mi) long and 2 metres (6 ft 7 in) above sea level at its highest point, though the protective dykes are 2.8 metres (9 ft 2 in) high.