U.S. Geological Survey Photographic Library

Expedition member in Santa Elena Canyon, October 1899.

In the 1880s and 1890s, even as settlers began to trickle into the Big Bend region, it remained largely undefined on maps. Following the Mexican War, American surveying parties followed the river to determine the boundary between the United States and Mexico, yet steered clear of the deep canyons found along this portion of the Rio Grande.

In October 1899, U.S. Geological Survey (USGS) geologist Robert T. Hill led a six man expedition to explore and document the canyons of the Rio Grande, a place he described as "the longest and least known." Traveling in three boats, the expedition took nearly an entire month to travel from Presidio to Langtry, Texas.

Hill packed photography equipment into the boats, and took a series of photographs, both during and after his river voyage. Two years later, Hill published an article describing his voyage, and describing the Big Bend region in the colorful language of the period.

The photographs shown here are a portion of the nearly 200 he took during his eighteen year career with the USGS, and vidly capture Big Bend just before Twentieth Century. All photos are in the collection of the U. S. Geological Survey Photographic Library.