The old name of the town/village (originally the island Kirkelandet) was Fosna or Fosen (Old Norse: fólgsn) which means "hiding place" (here 'hidden port').

Before the introduction of postal codes in Norway in 1968, it was easy to confuse the name Kristiansund with Kristiansand in the south.

The arms were granted by King Christian VI and are described as a silver or white river flowing from a cliff, with salmon jumping upwards on a blue background.

The most famous one was the Battle of Rastarkalv on the island of Frei, where the Norwegian King Håkon the Good fought against the Eirikssønnene group.

The natural harbour in Lille-Fosen, close to where Kristiansund is located today, was also frequently used for fishing purposes.

During World War 2 the town was one of the most heavily bombed cities in Norway, and the German occupation forces taking over the Allanengen school as a headquarters.

The landscape with its unique natural harbour combined with warm wind from the southwest of the Atlantic Ocean and the Gulf Stream gives Kristiansund a much warmer climate than its latitude would indicate.

Though fairly small in size, the town of Kristiansund contains many green parks and gardens, frequently used by the local inhabitants.

The Sundbåt bears the distinction of being the world's oldest motorized regular public transport system in continuous service.

After passing through the underwater Freifjord Tunnel from the central part of Krifast, National Road 70 crosses Frei, and enters Kristiansund over the Omsund Bridge onto Nordlandet.

There used to be a car ferry going from Kirkelandet island to neighboring Averøy Municipality to the west, whose people have been commuting to town for many years for work as well as selling agricultural products.

Besides roads and car ferries and Kristiansund Airport, Kvernberget, connections to/from Kristiansund consist of the traditional coastal express Hurtigruten boats which connect the coastal towns from Bergen in the south to Kirkenes in the north, as well as the high speed catamaran passenger service Kystekspressen to Trondheim.

Bacalhau is made of salted, dried codfish,[10] and has traditionally been exported in large amounts to Spain, Portugal, and Latin America as food suitable during Lent.

Due to the city's heavy involvement in fish processing and international shipping, there used to be as many as seven consulates in Kristiansund, mainly to Latin countries.