Mussurana montana is a poorly known dipsadid snake endemic to elevated areas in the Atlantic Forest of southeastern Brazil. After the examination of specimens deposited in scientific collections, we update the distribution range of M. montana with five new locality records, including its first record from the state of Rio de Janeiro, and a new northernmost and easternmost record in the state of Minas Gerais. These new data reinforce the distribution of M. montana within the mountain ranges of Serra da Mantiqueira and Serra do Mar, from 750-1,610 m above sea level.