Troms or Romsa is a county in North Norway, bordering Finnmark to the northeast and Nordland in the southwest. To the south is Norrbotten Län in Sweden and further southeast is a shorter border with Lapland Province in Finland. To the west is the Norwegian Sea (Atlantic ocean). The entire county, which was established in 1866, is located north of the Arctic circle. Until 1919 the county was formerly known as Tromsø amt. On 1 July 2006, the Northern Sami name for the county, Romsa, was granted official status along with Troms.
The county (and the city of Tromsø) is named after the island Tromsøya on which it is located (Old Norse Trums). Several theories exist as to the etymology of Troms. One theory holds "Troms-" to derive from the old (uncompounded) name of the island (Old Norse: Trums). Several islands and rivers in Norway have the name Tromsa, and the names of these are probably derived from the word straumr which means "(strong) stream". (The original form must then have been Strums, for the missing s see Indo-European s-mobile.) Another theory holds that Tromsøya was originally called Lille Tromsøya (Little Tromsøya), because of its proximity to the much bigger island today called Kvaløya, that according to this theory was earlier called "Store Tromsøya" due to a characteristic mountain known as Tromma (the Drum). The mountain's name in Sámi, Rumbbučohkka, is identical in meaning, and it is said to have been a sacred mountain for the Sámi in pre-Christian times.