This map, titled Map of the Valley of the Amazon to accompany Lt. Herndon’s Report, illustrates the broader geographic region covered by the first official U.S. exploratory expedition of the Amazon River system. Created under the direction of the U.S. Navy Department in 1853, the map extends from the Pacific coasts of Peru and Ecuador to the Atlantic mouth of the Amazon in Brazil. It illustrates the Amazon River's extensive basin and watershed, detailing the river system and its tributaries alongside the expedition routes taken by Lieutenants William Lewis Herndon and Lardner A. Gibbon.
The map was part of a larger report commissioned by the U.S. government to assess the navigability and potential for economic development in the Amazon Valley. Beginning in Lima, Peru, in May 1851, the expedition split into two groups. Lieutenant Herndon journeyed over 4,366 miles through Peru and Brazil, ultimately reaching Pará (modern Belém) on April 11, 1852, while Lieutenant Gibbon explored Bolivia and descended the Madeira River. Both routes are traced on the map, providing a comprehensive overview of the expedition's scope.
The map offers a detailed depiction of major rivers, tributaries, and significant geographic features, such as the Andes Mountains and the extensive jungle terrain. The annotations and renderings of elevation profiles further emphasize the diverse and challenging landscapes encountered during the journey.
Prepared to accompany Lieutenant Herndon’s published report, the map was disseminated widely, reflecting the growing American interest in the Amazon as a frontier for exploration, commerce, and resource exploitation. Its precision and inclusion of expedition tracks make it a significant historical artifact documenting early U.S. involvement in South American exploration.