64°52′00″N 21°15′00″W / 64.866667°N 21.25°W [1] Norðurárdalshreppur (Icelandic pronunciation: [ˈnɔrðʏrˌaurˌtalsˌr̥ɛhpʏr̥]) was formerly a rural parish ( hreppur) in Mýrasýsla county, west Iceland. On 11 June 1994 Norðurárdalshreppur united with Borgarnes, Hraunhreppur and Stafholtstungnahreppur under the name Borgarbyggð.