Norrbotten County (Swedish: Norrbottens län; Northern Sami: Norrbottena leatna, Finnish: Norrbottenin lääni) is the northernmost county or län of Sweden. It is also the largest county by land area, almost a quarter of Sweden's total area. It borders Västerbotten County to the southwest and the Gulf of Bothnia to the southeast, as well as the counties of Nordland and Troms og Finnmark in Norway to the northwest, and Lapland Province in Finland to the northeast.
The name "Norrbotten" is also used for a province of the same name. Norrbotten province covers only the eastern part of Norrbotten County – the inland mostly belongs to the Swedish Lapland province (Lappland).
The capital of Norrbotten is Luleå, whereas other significant towns include Boden, Kiruna and Piteå. The majority of the population lives in the namesake province, whereas the Lapland part of the county is sparsely populated. In terms of land area, Norrbotten is larger than both Austria and Portugal as well as the island of Ireland.
The northern part of Norrbotten lies within the Arctic Circle.