Originally published in 1915 as a reprint from the Oregon Historical Quarterly, Pacific Coast Survey of 1849 and 1850 by Lewis A. McArthur chronicles the first systematic United States Coast Survey expeditions along the western seaboard. The monograph details the arduous hydrographic and topographic mapping efforts led by the author’s grandfather, naval lieutenant William Pope McArthur, which transformed the rugged Pacific coastline and the treacherous Columbia River into navigable, standardized maritime charts. Through detailed geographic logs and biographical accounts of the grueling expedition, the text documents the foundational cartographic work that literally put the newly acquired territories on the American administrative map. A keen insight drawn from the work is how supposedly objective scientific surveys functioned as the primary vanguard of colonial incorporation; by systematically translating indigenous coastlines into legible, federal hydrographic data, early surveyors provided the essential infrastructure that accelerated commercial shipping, military control, and rapid settler expansion in the Pacific Northwest.