From a geographical point of view it would be the continent of Antarctica and a countries like Greenland , Norway plus northern Alaska (all countires near the poles) because of the tilt of the Earth.
For a funny answer most countries in the tropics have 6 months od daylight and 6 months of darkness because their days are divided into apprx 12 hours of daylight and 12 hours of darkness.

The Artic and the Antarctic regions

Norway

Greenland

Occurring in summer months at latitudes north and nearby to the south of the Arctic Circle, and south and nearby to the north of the Antarctic Circle where the sun remains visible at the local midnight. Given fair weather, the sun is visible for a continuous 24 hours, mostly north of the Arctic Circle and south of the Antarctic Circle. The number of days per year with potential midnight sun increases the farther poleward one goes.There are no permanent human settlements south of the Antarctic Circle, so the countries and territories whose populations experience it are limited to the ones crossed by the Arctic Circle, i.e. Canada, United States of America (Alaska), Denmark (Greenland), Norway, Sweden, Finland, Russia, and extremities of Iceland. A quarter of Finland\'s territory lies north of the Arctic Circle and at the country\'s northernmost point the sun does not set for 73 days during summer.