The location named Hahamongna was the Tongva village located in the upper Arroyo Seco area just above the Devil's Gate dam in the present day Altadena-Pasadena-Jet Propulsion Laboratory-JPL area. It is in the Arroyo Seco canyon-valley and on the lower slopes where the eastern Verdugo Mountains, southern San Gabriel Mountains, and western San Rafael Hills meet. The site of Hahamongna is now within the protected natural area of Hahamongna Watershed Park, a 1,400-acre (5.7 km2) blend of freshwater marsh wetlands, riparian zones, native oak woodlands, and chaparral elfin forests.