Perched at at 4,500 meters (nearly 14,800 feet) on the edge of the northern Chang Tang Plateau, Nagchu (Naqu in Mandarin) is one of Tibet's highest towns (the highest is Wenzhuan, along the Qinghai-Tibet Highway at the border over 200 kilometers to the north at 5,100 meters).
Nagchu is also, unsurprisingly, one of the coldest and windiest cities in Tibet, conditions that deter both visitors and agriculture. Despite the harsh environment, Nagchu is home to nearly 70,000 people as well as many more hardy sheep and goats—they're the staple here, where oxygen levels are just 60% of those found at sea level. If you find yourself in Nagchu, keep in mind that even those acclimated to Lhasa's altitude are likely to feel the effects of the height and thin air here.
Although Nagchu doesn't really offer any tourist attractions, an annual August Nagchu Horse Racing Festival attracts some 10,000 nomads eager to show off horsemanship skills, trade for tools and supplies, and celebrate the brief Tibetan summer.
The Tibet-Qinghai (Qingzang) Railway Nagch stop is designated as a station with a vista point. In recent years, special permits have not been required to visit Nagchu, though you'll want to check ahead to be certain.