1918 Map of Porcupine Valley

About this map

Porcupine Valley defines this section of Valley County during the late 1910s, revealing a landscape of winding drainages and complex coulees. This 1918 edition, based on earlier surveys by the General Land Office and R.C. Seitz, documents the natural hydrology of the Missouri River watershed before modern water management altered the plains. The confluence of Porcupine Creek and its East Fork forms a central spine through the terrain, flanked by notable geological features like Enright Coulee and Sargent Creek. For researchers, the map provides a precise record of the public land survey system lines and early topography in a region defined by its seasonal watercourses, including Cherry Creek and Cherry Coulee, which shaped the early paths of travel and homesteading in the Montana high plains.