Routes Near the 47th and 49th Parallels Profiles From Explorations and Surveys Made Under the Direction of the Hon. Jefferson Davis, Secretary of War

Examining elevation changes along possible routes for America’s first Transcontinental Railroad.

This series of topographic elevation profiles captures one of the most critical cartographic deliverables of the mid-19th century: the 1853–1855 Pacific Railroad Surveys. Published as part of the monumental multi-volume reports ordered by Secretary of War Jefferson Davis, this sheet illustrates the northernmost route, the 47th and 49th Parallel survey, conducted under the leadership of Isaac I. Stevens, the first Governor of Washington Territory. Lithographed in New York by the prominent firm of Sarony, Major & Knapp, the sheet translates complex barometric measurements and transit surveys into a clear, comparative visual guide meant to demonstrate the feasibility of a transcontinental railway connecting the Upper Mississippi to Puget Sound.

The sheet is dominated across the upper quarter by a continuous “General Rail-Road Profile” tracing the proposed line from the Milk River Crossing in present-day Montana through Cadotte’s Pass across the Continental Divide, navigating the Coeur d’Alene Mountains and the Cascade Range via Snoqualmie Pass, and descending to its ultimate terminus at Seattle. Below this main profile, the layout features detailed sectional cross-sections isolating specific mountain passes and difficult terrain segments encountered by Stevens’ party. Along the bottom margin, another extensive “General Profile” details the line from the mouth of the Judith River to Camp Stevens in the Bitterroot Valley, explicitly highlighting gradient ratios, elevation changes, and mountain passes essential for 19th-century locomotive engineering.