Øvre Pasvik occupies 119 square kilometers of the Pasvikdalen valley in Sør-Varanger Municipality, Finnmark. Its western border runs precisely along the Finland-Norway frontier. To the east lies the Norway-Russia border and the joint Pasvik Nature Reserve. At the park's edge stands Treriksrøysa, the tripoint cairn marking the exact spot where all three countries meet. The park is part of the larger Pasvik-Inari Trilateral Park, a cross-border conservation zone that extends into Finland's Vätsäri Wilderness Area and the Russian side of the nature reserve. In 2024, it became Norway's first certified International Dark Sky Park. The terrain is remarkably flat by Norwegian standards, its highest point, Kolfjellet, reaching only 260 meters above sea level. Rolling hills covered in ancient forest give way to shallow lakes, tarns, and expanses of bog. The underlying rock is mostly granite gneiss, blanketed in soil so thick that bedrock only shows itself in occasional cliffs and hillocks.

Half the park is covered in old-growth Scots pine, and these trees live on a timescale that makes human planning seem hasty. A typical tree is between 300 and 400 years old. Reproduction is painstakingly slow: the pines need two consecutive warm years to produce cones, and young trees often die when moose eat their buds during winter. Wildfire has been the forest's great editor, most recently in 1945. Fire moves through the undergrowth, sparing mature pines whose branches start high above the flames but incinerating younger generations wholesale. The result is a forest with an uneven, gap-toothed age distribution. On the islands in Ellenvatnet, however, fire has never reached, giving those stands a uniquely continuous composition. Norway spruce, dominant just across the Russian border, barely exists here. Late frosts that persist into June, combined with wildfire, keep the spruce population to scattered clumps of no more than forty trees. About 190 species of flowering plants have been documented, and in August the bogs yield cloudberry in generous quantities.

Brown bears hibernate in the park, and each year two to four females raise cubs within its boundaries and the adjacent landscape protection area. The bears treat the three national borders as irrelevant, moving freely between Russia and Finland as instinct dictates. Moose populations have been growing, and their browsing is now reshaping the forest itself by suppressing regrowth. Eurasian lynx sometimes pass through. Laxmann's shrew, a small mammal found in very few places in Norway, lives here. The bird life tilts heavily Siberian: Siberian jays, pine grosbeaks, Bohemian waxwings, and common cranes share the canopy with great grey owls and northern hawk-owls, whose numbers swell in years when rodent populations boom. Osprey hunt over the lakes of Ellenvatnet and Ødevatnet. Eight species of fish inhabit the park's waters, with brown trout having arrived via the river system around 8000 BC, while the other species filtered in after the last ice age from Lake Inari and the then-freshwater Baltic Sea.

People have inhabited the Pasvikdalen since at least 4000 BC, when the Komsa culture left archaeological traces. Around 2300 BC, immigrants arrived from Finland, and later the Skolt Sámi used the area extensively for reindeer herding. Norwegian settlement began around 1850, and the first farm was established in 1874 after a road reached the valley. Author Carl Schøyen first proposed protecting the area as a national park in 1936, sending his case to the Ministry of Agriculture. The ministry rejected it outright, philosophically opposed to conservation at the time, preferring that all natural resources be exploited. Schøyen tried again in the late 1940s, and in 1951, the year he died, the Director of Forestry quietly protected 70 square kilometers by administrative order. The national park was formally established on February 6, 1970, covering 66 square kilometers. It was expanded to its current 119 square kilometers in August 2003.

Øvre Pasvik has no recreational infrastructure whatsoever. No maintained trails, no cabins, no signage within the park itself. Visitors simply walk in and navigate as best they can through the bog and forest. Motorized vehicles are prohibited; canoes and skis are permitted. Hunting and fishing require licenses. Dogs must be leashed between April 1 and August 20. The national park center, co-located with the NIBIO Svanhovd research station at Svanvik, sits 40 kilometers south of Kirkenes and offers films and exhibits. Three side roads off National Road 885 provide car access to the park's edges. One terminates near Svartbrysttjern, another at Ødevatnskoia close to Ødevatnet, and a third runs through the landscape protection area to Grensefoss, roughly five kilometers from the tripoint cairn where three countries meet in the wilderness.