There are 22 urban districts in the Netherlands, accounting for 56 percent of the Dutch population (1 January 2007). The urban districts consist of a central municipality (the central city) and a number of nearby municipalities.
An urban district is a conglomeration of one or more urban agglomerations and the surrounding rural area, which are connected with each other through all sorts of relationships. The delineation of urban districts is based mainly on the relationships on the regional labour market and the regional housing market. The urban district of Groningen consists of the municipalities Bedum, Ten Boer, Groningen, Haren, Leek, Marum, Noordenveld, Tynaarlo, Winsum and Zuidhorn.