Kalsoy´s rich birdlife is not limited to the island’s green valleys and slopes, the northern cliffs are also alive with birds. At its southern tip, Galvur, and to the north, the island plays host to several interesting and rare plants.
Reaching a height of 787 metres, Nestindur is Kalsoy´s highest peak.
Four villages are found on the island, all located on its east side. Beginning from the south, they are Syðradalur, Húsar, Mikladalur and Trøllanes. At one time, a village, Blankaskáli, was also found on the island’s western side.
Syðradalur and Húsar form Húsar municipality, while Mikladalur and Trøllanes are part of of Klaksvík municipality.
As of 2015, according to official statistics, six people live in Syðradalur, 40 in Húsar, 29 in Mikladalur and 16 in Trøllanes.
The island is serviced by a ferry, sailing several times a day between Klaksvík and Syðradalur. The villages are connected by road and four tunnels. The tunnel between Mikladalur and Trøllanes also opens up to the valley Djúpadalur.
From the south, Villingadalur tunnel is from 1979 and is 1,193 m long. Next is Ritudalur tunnel, built in 1980 and 683m long. Mikladalur tunnel from 1980 is 1,082 m long. And lastly, the Trøllanes tunnel, from 1985, is 2,248 m long, and the stretch out to Djúpadalur is 220 m long.
A memorial for those lost at sea was erected in Syðradalur in 2000 and a sculpture, the Seal Woman, on the shore of Mikladalur in 2014. Small school houses are found in all villages. Lutheran churches are found in Húsar and Mikladalur, and the Brethren have the assembly house Malta in Mikladalur. A campsite is also located in Mikladalur. Light houses are found south of Syðradalur and on Kallur, the northern tip of the island. Húsar and Mikladalur have each their own village hall.
A smolt farm is in the valley Knúsdalur, located between Syðradalur and Húsar. Meals can be purchased in Húsar, a coffee shop is found in Mikladalur and Trøllanes hosts a smithy and a kiosk.