Although the waters of Borgarfjörður appear calm, the fjord has significant undercurrents and shallows.
The many flat islands lying in the fjord are for the most part uninhabited.
The land around the fjord has been inhabited since the time of Icelandic settlement.
While serving as a synonym for the various townships, farms, natural attractions and areas in the region, the various parts of Borgarfjörður are now generally referred to as Borgarbyggð, a name that in Icelandic denotes residential areas, populated places, such as Borgarnes, tourist resorts and attractions, and less populated farms and more remote natural areas.
The name Borgafjorður refers to the actual fjord and surrounding beaches as a natural habitat.