Sejerø is a Danish island in the Kattegat sea, north-west of Zealand. Sejerø with its 400 inhabitants is part of Kalundborg Municipality and covers an area of 12.36km². The largest village on Sejerø is Sejerby, housing half of the island's population.South-east of Sejerø is the smaller island of Nekselø, also in the Bay of Sejerø.Sources Tageo.com, "VESTSJAELLAND DENMARK Geography Population" (coordinates), 2007, webpage: Tageo-Sejero. Denmark Postal codes, webpage: Postnumre-DK. Tele.dk Denmark detailed road map, webpage: Tele-DK-Danmark.