Juan María Marrón (February 8, 1808–September 17, 1853) was an early settler of San Diego, California.
Marrón was a ship's captain before settling San Diego in the early 1820s. In 1834 Marrón, married Felipa Osuna (c. 1818–December 21, 1871), the daughter of Juan María Osuna. They had three sons and one daughter.
Marrón served as the first Alcade of the Pueblo of San Diego during 1 January 1835 – 1836. He also served as Regidor (Alderman) and Juez de Paz (Justice of the Peace).
Marrón was granted Rancho Agua Hedionda in 1842, which is in the southern coastal part of present-day Carlsbad. Agua Hedionda means "stinking water", named after decayed organic material in the Agua Hedionda Lagoon.
During the Mexican-American War Marrón supported the Americans. This caused him hardship and embarrassment with his friends. Once incident was related by Richard F. Pourade in The Silver Dons:
Later Rancho Agua Hedionda was acquired and held by the Kelly family for many years. The adobe home of Marrón still stands, although modernized in the 1960s.
Marrón died in 1853 and is buried in El Campo Santo Catholic Cemetery in Old Town San Diego. His wife Juliana died in 1871 and was buried next to him.