Lake Þveit is in Nesjahreppur in A.-Skaftafellssýsla, just north of Hafnar in Hornafjörður. The lake is 0.91 km², very shallow and only 2 m above sea level. The creeks Myllulækur and Skrápslækur flow to it and Þveitarlækur from it to river Hornafjarðarfljót. The lake contains local Arctic char, brown trout, sea trout and sea char. There is access between the lake and the sea, so that sea trout can make their way to the lake. There are large numbers of small Arctic char in the lake and there are also stories of beautiful brown trout that have been caught there. The best time for fishing is in spring and autumn.