Being the most beautiful country in Europe, Norway is as rich in unspoiled wild nature as it is in oil. The rugged mountains are interspersed with endless plateaus full of lakes. Impressive fjords (sea inlets) and glaciers ornament the long coastline. The unforgettable spectacle of a thunderstorm drifting by, the sun breaking through, the rain drifting away in the distance. In the Home of Giants (Jotunheimen) you will feel tiny as a dwarf. North of the polar circle there are several splendid areas like Troms and Finmark. Do bring your fishing gear if you go there.
Norway does not have long distance trails, but for some exceptions. Wherever there is wilderness, there are mountain huts interconnected by trails marked with a red "T". Often these are painted high on heaps of stone, in order to stick out above the snow. The majority of huts are exploited by the DNT. Others by local hiking organisations. Some huts are private. Some of the huts are staffed and meals are served. Others are self-service huts: there is food in store, you take what you like, write down what you ate, and leave money for it in a special box. The third type of hut is the no-service hut. Here, you have to carry your own food. Generally they are equiped with gas, firewood, kitchen utensils, and blanks. Often, you will need a key to get in. The standard DNT key, which you can arrange in advance, fits on all huts.
All this means you can leave your tent at home, unless you prefer to camp in the wild clear light summer nights, and wake up to find yourself surrounded by a herd of ruminating reindeer.
A beloved national park is Rondane. Also, of course, Jotunheimen with Norway's higest mountains Galdhøpigen and Glittertind, is very popular. South of Jotunheimen is the vast plateau of Hardangervidda. The main hiking area's are situated in the south of the country. Turning north, the mountains are less well serviced by huts, and consequently hiking is more adventurous. Head north if you're looking for silence and real wilderness. A part of Lappland is in Norway and you can go there and sleep in reindeer farms: Finnmarksvidda.
Be aware that in Norway as in every country the Long T(r)ail theory is valid: most of the hikers go to 10% of the area's. But other area's may be more beautiful and in any case more quiet. In the north for instance, you will encounter a string of intensely beautiful mountain plateaus and ranges: Okstindan in Nord-Helgeland, Saltfjellet, Sulitjelma, and more. If you don't mind carrying your own food, meeting few people and 24 hours light a day, this is the place to go. Between simple but well furnished huts, cairned routes are laid out, leading up all the way to Lapland, even to Kautokeino via the Nordkalott trail and the Nordlandsruta. You can walk for months. Check out the DNT website, your most important source of information.
The season for walking the mountains is short. In June you will still sink down deep into the snow in the mountains. And again in September fresh snow is likely to blow you right off the fjell. Hiking in Norway is not without risk. River crossing and extremely bad weather take their toll. On warm days with no wind, the notorious midges will attack relentlessly.