Major southern Norwegian salmon and sea-trout river, one of the country's longest, running from Numedal down through Vestfold to the sea at Larvik. A strong public-facing angling identity around Larvik, Holmfoss, Brufoss, Naugfossen, Hoggtveita, Kjærrafossen and Hvittingfoss, with good fly-fishing conditions at Brufoss. Regulation is split by reach: the lower river (mouth to Holmfoss) opens earlier than the upper river (Holmfoss to Hvittingfoss). A daily quota of one fish applies, and the season is subject to a mid-season evaluation that can extend, tighten or stop fishing. Managed by Numedalslågen forvaltningslag; beats bookable via Elveguiden, Inatur and local club/member waters. A good page should separate lower-river early season from upper-river later season. Atlantic salmon are managed under a daily quota of one fish per angler, with a mid-season evaluation that can tighten, extend or stop fishing; any further fish must be released.
- Mixed

