Pico 31 de Março, Mountain summit on the Brazil–Venezuela border, Amazonas

Pico 31 de Março is a rounded summit on the Brazil–Venezuela border in the Neblina massif, reaching 2,974.18 m. It lies 687 m from Pico da Neblina, Brazil's highest point, to which it is linked by a short col traversable in about an hour. The massif is a glaciated tor of tilted sandstone over Precambrian metamorphic rock.

The peak was first sighted in 1954 during Basset Maguire's expedition to the north side of the massif, and it was climbed during the Brazilian army's first attempt on Pico da Neblina. Its name, meaning "March 31 Peak", was a self-homage by the military regime installed in the 1964 coup, officially called the "March 31 Revolution". The name was kept after the return to democracy in 1985.

The peak lies in demarcated Yanomami territory and in Pico da Neblina National Park, so visits require ICMBio authorisation and an accredited local guide from São Gabriel da Cachoeira. The name Neblina means "fog" in both Portuguese and Spanish, a reference to the clouds that often cover the massif.

Reaching the summit requires at least four days of trekking through thick jungle with experienced local guides who know the terrain. You will need advance permissions from authorities in São Gabriel da Cachoeira, and you should prepare for high humidity, rough trails, and frequent rain.

The 1965 theodolite measurement by topographer José Ambrósio de Miranda Pombo gave 2,992 m and stood uncontested for 39 years. A 2004 GPS survey by cartographer Marco Aurélio de Almeida Lima revised it to 2,972.66 m, and in 2016 IBGE recalculated the official height to 2,974.18 m without a new field expedition.