About Marsh Valley
Marsh Valley lies in the mountains of southwestern Idaho at the heart of Bannock County. It is a rural valley of serene beauty and surrounded by ridges of the Rocky Mountains. Marsh Creek flows the length of the valley along its western side and the Portneuf River flows in on the eastern side and flows north along that side of the valley until the two meet at the north end of the valley. Between the two lies an ancient lava flow which protrudes from the vegetation in black cliffs. Old Tom Mountain and its companion, Scout Mountain forms the wall of the valley at the northwest side and the Portneuf Mountains line it on the northeast side. Elkhorn Mountain and Oxford Mountain stand at the south end of the valley. At the north end of the valley, the Portneuf River makes a bend to the west and passes through the Portneuf Gap, leading to Pocatello and the Snake River Basin.
Marsh Valley is an important avenue of travel through this corner of Idaho and always has been, providing a natural pass through the surrounding mountains. The Oregon Trail passed through the valley following the Portneuf River and using the Portneuf Gap. The first railroad in Idaho passed through Marsh Valley, extending northward from Utah. Today Interstate 15 traverses the valley north to south and U.S. Highway 30 crosses it, following the route of the Oregon Trail. U.S. Highway 91 shares an alignment with I-15 today, but before the freeway was the main route of travel for the towns of the valley, and its old alignments can still be travelled today.
The elevation of Marsh Valley is about 4,600 feet and the surrounding mountains reach to around 9,000 feet. The rural towns of Inkom, McCammon, Arimo and Downey are found here, along with acres of ranchland and scattered farmhouses.