The Martín Peña Channel is a body of water in San Juan, Puerto Rico. The similarly named Martín Peña is a neighborhood, with informal housing, adjacent to the channel.

San Juan is the capital city and most populous municipality in the Commonwealth of Puerto Rico, an unincorporated territory of the United States. As of the 2020 census, it is the 57th-largest city under the jurisdiction of the United States, with a population of 342,259. San Juan was founded by Spanish colonists in 1521, who called it Ciudad de Puerto Rico.