Honningsvåg in Finnmark claims to be the northernmost city of the world, and Vardø is the easternmost town in Norway and is farther east than Istanbul.

This valley has the highest density of Brown bears in Norway, and is the only location in the country with a population of musk-rats, resulting from their introduction from their native North America into Europe in the early 20th century which included their release in a total of 293 localities all over Finland from 1919 and onwards, and then of ca 1,000 muskrats on the Kola Peninsula during 1931–1936.

The plateau is famous for its tens of thousands of reindeer owned by the Sami, and swarms of mosquitos in mid-summer.

Due to the proximity to the ice-free ocean, winters are much milder in coastal areas (and windier).

Skibotn in Storfjord Municipality is the location in Norway which has recorded the most days per year with clear skies (no clouds).

Lakselv Airport Banak in Porsanger Municipality has a boreal climate with sparse precipitation.

Situated far north of the Arctic Circle, Troms og Finnmark has midnight sun from the middle of May until late July.

At midwinter, there is only a bluish twilight for a couple of hours around noon, which can almost reach full daylight if there are clear skies to the south.

The county is situated in the Aurora Borealis zone, and because of the dry climate with frequent clear skies, Alta Municipality was early chosen as a location for the study of this strange light phenomenon.

Southern and mid-Troms was a Norwegian petty kingdom in the Viking Age, and considered part of Hålogaland.

According to the sagas, Tore Hund speared King Olav Haraldsson at the Battle of Stiklestad.

The Sami are the indigenous people of the area, but Norwegians have lived for hundreds of years on the islands' outer parts, where they made up the majority.

The Sami people still constitute the majority in Finnmark's interior parts, while the fjord areas have been ethnically mixed for a long time.

In the midst of this awakening (1979), Norway's government decided to build a dam in Alta to produce hydropower, provoking many Sami and environmentalists to demonstrations and civil disobedience (Altasaken).

In the end, the dam was built on a much smaller scale than originally intended and the Sami culture was on the government's agenda.

Coastal areas of Finnmark were colonized by Norwegians beginning in the 10th century, and there are stories describing clashes with the Karelians.

Ergotism from contaminated flour has been suggested as a likely cause for the frequent trials, as most grain in Finnmark was imported and may have been of low quality.

In 1866, the island of Senja and the Troms area were separated from Vardøhus to form the new Tromsø amt.

Per Fugelli has said that World War II resulted in many persons acquiring psychiatric disorders (psykiske senskadene) which could be from experiencing "bombing, accidents involving mines, burning down of homes, forcible evacuation, illness and starvation during the war and liberation.

"[17] Towards the end of World War II, with Operation Nordlicht, the Germans used the scorched earth tactic in Finnmark and northern Troms to halt the Red Army.

As a consequence of this, few houses survived the war, and a large part of the population was forcefully evacuated further south (Tromsø was crowded), but many people avoided evacuation by hiding in caves and mountain huts and waiting until the Germans were gone, then inspected their burned homes.

The government imposed a temporary ban on residents returning to Finnmark because of the danger of landmines.

[citation needed] The Cold War was a period with sometimes high tension in eastern Finnmark, at the 196-kilometre (122 mi) long border with the Soviet Union.

A county-wide non-binding referendum was held in which it was opposed by about 87% of Finnmark residents who voted,[20] but the Storting did not reverse its decision to merge the county.

Some political parties campaigned to reverse the merger in the parliamentary term that starts in September 2021.

[21] On 28 October 2021, Minister of Local Government Bjørn Arild Gram sent a letter to the county confirming that it will be demerged.

On 1 January 2019, Elisabeth Aspaker was appointed as the County Governor of Troms og Finnmark.