The Regional District is the largest in the province, comprising 13% of its area. At 119,200 km2 (46,023 mi2) it is similar in area to the American state of Pennsylvania or New Zealand's North Island. The northern border along the 58th parallel north was created when the PRLRD split to create the PRRD and the NRRD. The Regional District borders with six municipal districts in Alberta to the east - the Municipal District of Greenview No. 16, the County of Grande Prairie No. 1, Saddle Hills County, Clear Hills County and the County of Northern Lights. The southwestern border runs along the Rocky Mountains, beginning at Intersection Mountain then northwesterly along the summit of the Hart Ranges to Williston Lake and then northwesterly along the watersheds of the Manson, Omineca, Mesilinka, Finlay, and Kechika rivers.