Pico 31 de Março, or Pico Trinta e Um de Março in full, also known as Pico Phelps, is a mountain on the Brazil–Venezuela border. At 2,974 metres (9,757 ft) above sea level, it is Brazil's second highest mountain. It is part of the Neblina massif, and the latter's summit Pico da Neblina, Brazil's highest summit, is only 687 m (2,254 ft) away. Pico 31 de Março can be considered a secondary summit of Pico da Neblina. Therefore, it is usually climbed by expeditions primarily aiming to reach the other peak. The two are linked by a col that can be easily traversed in a short trek of about an hour.

Pico da Neblina is the highest peak in Brazil, 2,995.3 metres (9,827 ft) above sea level, in the Serra da Neblina, part of the Serra do Imeri, a section of the Guiana Highlands on the Brazil-Venezuela border. As determined by a border survey expedition in 1962, its summit lies just within Brazilian territory, at a horizontal distance of only 687 m (2,254 ft) from the Venezuelan border at Pico 31 de Março. It is a common misconception to refer to this mountain as the highest point in South America outside the Andes while ignoring the Sierra Nevada de Santa Marta in Colombia.