The municipality was established by the 1970 reforms which grouped parishes into municipalities. Aars municipality was made up of the parishes of: Blære, Gislum, Giver, Gundersted, Havbro, Skivum, Ulstrup, Vognsild, and Aars parish.[citation needed]
By 2005, the municipality covered an area of 223 km2 and had a total population of 13,284. Its final mayor was Knud V. Christensen, a member of the Conservative People's Party.[citation needed] On 1 January 2007 Aars municipality ceased to exist and was merged with the former Farsø, Løgstør, and Aalestrup municipalities to form the new Vesthimmerland Municipality, with an area of 815 km2 and a total population of 39,176 (2005).[1]