From the Wikipedia page 
Roskilde municipality (Danish: Roskilde kommune) is a municipality in Region Sjælland, 30 km west of Copenhagen on the island of Zealand (Sjælland) in east Denmark.
The biggest city is Roskilde, the municipality covers an area of 212 km², and it has a total population of 80,687 (2008). Its mayor is Joy Mogensen. She is a member of Socialdemokraterne.
Neighboring municipalities are Egedal to the northeast, Greve and Solrød to the southeast, Høje-Taastrup to the east, Køge to the south and Lejre to the west. To the north-west is Roskilde Fjord.
By January 1, 2007 the former Roskilde municipality was merged with Gundsø and Ramsø municipalities into the current one, as the result of Kommunalreformen ("The Municipal Reform" of 2007). The name of the new municipality is still "Roskilde Kommune". The town hall is situated in the city of Roskilde, at Køgevej 80.
It formerly belonged to Roskilde County.