Pico da Neblina is often mentioned as being on the border between the two countries, but this would be taking in consideration its massif as a whole, and not just the main summit.
Pico da Neblina is the highest point in the Guiana Shield, but unlike famous Monte Roraima, it is not a tepui, as the unique tabletop mountains of the Guiana Highlands are known. Tepuis are only found far to the northeast of the Imeri range. Furthermore, Pico da Neblina is not table-shaped, but a rather sharp peak.
The word neblina means "fog" in both Portuguese and Spanish; so, the peak's name (meaning "Peak of the Mists") reflects that it is shrouded in dense clouds most of the time. It was first ascended in 1965 by members of a Brazilian army expedition.
The mountain is contained in the Brazilian Pico da Neblina National Park; its northern slopes are also protected in Venezuela's Serranía de la Neblina National Park. The twin parks, together with the neighbouring Parima-Tapirapecó National Park (Venezuela), form a protected area complex of about 80,000 km², possibly the largest national park system in tropical rainforests in the world.
For 39 years, based on an uncontested measurement performed in 1965 by topographer José Ambrósio de Miranda Pombo, using a theodolite, the elevation of Pico da Neblina was thought to be 3,014 metres (9,888 feet), but a much more accurate measurement performed in 2004 with state-of-the-art GPS equipment by cartographer Marco Aurélio de Almeida Lima, a member of a Brazilian army expedition, puts it at 2,994 metres (9,822 feet). This is now recognised by the Brazilian Institute of Geography and Statistics (IBGE), the federal government's official geographic survey and census agency, which jointly organised the expedition.
Pico da Neblina is a glaciated tor composed of a tilted block of sandstone overlying Precambrian metamorphic rocks. The peak is an impressive sharp rock pyramid or tooth towering high over the nearby lowlands on the Brazilian side, as the Imeri range rises steeply from only about 100 metres above sea level to 2,994 metres in only a few kilometres. The Venezuelan side is a little hillier and somewhat less steep. Neighbouring Pico 31 de Março can be considered a secondary summit of Pico da Neblina; it has a smoother, rounder shape and is sometimes difficult to be clearly distinguished from Pico da Neblina on photographs, depending on angle and distance. Due to Pico da Neblina's equatorial latitude, there is no snow.
The area's extreme remoteness, the peak's unusual and unexpected elevation next to the low-lying Amazon Basin, and the fact that Pico da Neblina is mostly clouded (hence its name) led to it only being discovered in the 1950s, supposedly by an airline pilot who flew over it at a luckily cloudless moment, the legend goes in Brazil. However, the massif had been previously known on the Venezuelan side as Cerro Jimé, and the area was visited by an expedition led by eminent Venezuelan ornithologist William H. Phelps, Jr. in 1954; as a tribute to him, Pico da Neblina is sometimes named Cerro Phelps in Venezuela.
In the 1950s, it was not yet clear whether the summit of Pico da Neblina was in Brazilian or Venezuelan territory, and its precise elevation was not yet known. Therefore, it was widely held for many years after the peak's discovery that Brazil's highest mountain was Pico da Bandeira (2,892 m or 9,488 ft), between the southeastern states of Minas Gerais and Espírito Santo, in a much more populated, developed and easily accessible region. Only in 1965 it was found and became widely known that Pico da Neblina was the country's highest mountain. Pico da Bandeira remains the highest Brazilian mountain outside of the Amazon region.
Due to its location in a national park in a border area that is also part of Yanomami territory, access to the area is restricted and depends on a special permit by the Brazilian Institute of Environment and Renewable Natural Resources (IBAMA). The permit can be obtained at IBAMA's office in São Gabriel da Cachoeira, but all climbers must take an accredited local guide. A four-day trek each way should be expected, three of which consisting of a jungle trek in the rainforest that can be as hard and challenging as the climb itself.
There are always some gold panners on a small plateau just below the peak, at about 2,000 m (6,100 ft), called Garimpo do Tucano, which serves as a base camp for the last and steepest part of the climb. While the panners' presence there is technically illegal, they are widely tolerated by Brazilian authorities, because in such a remote area, they are believed to watch the border and nature better than IBAMA's rangers and the army would have the means to do. Climber expeditions report them to be very friendly and helpful.