A History of America in 100 Maps

132 A HISTORY OF AMERICA IN 100 MAPS

The map on the previous page captures the

assumption—first articulated by Thomas Jefferson—

that the Louisiana Territory would become a

permanent home to Native Americans. That vision

of the future, however, was complicated when

thousands of Americans migrated across the Great

Plains to the Far West. Farmers began heading to

the fertile lands of Oregon’s Willamette Valley in the

1830s. In the 1840s, Mormons migrated west to flee

persecution, followed by thousands of prospectors

streaming toward the gold fields of California.

These migrants brought Oregon and California

into the American imagination well before those

areas were part of the national domain. At the

same time, the explorer John Charles Fremont

made a series of expeditions that vastly enlarged

American geographical knowledge of the western

interior. Fremont’s expeditions were facilitated by

his marriage to Jessie Benton, daughter of Missouri

senator Thomas Hart Benton. A champion of Manifest

Destiny, Benton forcefully advocated the annexation

of Texas, and sponsored Fremont’s western

expeditions as a way to bring the Far West under

American control.

Fremont’s extended journey of 1843 took him

through Oregon and California. Upon his return, his

wife developed his detailed field notes into a memoir

that burnished his reputation and advanced his

political career. Even more consequential than the

memoir were the maps produced by Charles Preuss, a

German immigrant who had joined two of Fremont’s

expeditions. Despite a sour temperament and an

abiding hatred of the outdoors, Preuss created some

of the most important maps of the American West in

the 1840s. Among the most impressive of these was a

seven-sheet series of the Oregon Trail.

OPENING THE OREGON TRAIL

Charles Preuss, “Topographical Map

of the Road from Missouri to Oregon,”

from the field notes and journal of

Capt. J. C. Fremont, section IV, 1846