Zeeburg (Dutch pronunciation: [ˈzeːˌbʏr(ə)x]) is a former borough of Amsterdam. It had 52,701 residents (January 2009) and an area of 19.31 km². The construction of new islands to the east called IJburg made it the most rapidly growing borough of Amsterdam. On 1 May 2010 Zeeburg merged with the borough of Amsterdam-Oost.