Hvalfjarðarsveit additionally borders the municipalities of Kjósarhreppur in the south, Akranes in the west, Borgarbyggð and Skorradalshreppur in the north, and Bláskógabyggð in the highlands to the east.

Notable lakes (from west to east) include Eiðisvatn, Hólmavatn, Eyrarvatn, Glammastaðavatn, Geitabergsvatn and Hvalvatn.

Iceland's second-tallest waterfall, Glymur, forms part of the river Botnsá that runs from Hvalvatn into the eastern bottom of Hvalfjörður.

[2] Some 30 km (19 mi) of the Ring Road pass through Hvalfjarðarsveit, between the Hvalfjörður Tunnel in the south and Borgarnes in the north.

[9] Pollution in the region caused by sulphur dioxide and fluorine emissions from the industrial area is controversial.