CITY OF ROCKS, Idaho — Hundreds of thousands of American immigrants once passed through the granite spires of Idaho's City of Rocks, branching off the Oregon Trail onto the California Trail in search of gold and fertile farmland in Northern California.
WATCH: See evidence of the 250,000 pioneers who once traveled west
From 1843 to 1882, the Oregon and California trails shared the same route through Missouri, Kansas, Nebraska, and Wyoming before splitting in the Idaho Territory.
"Up here by Raft River, the California trail broke off and came through Idaho, down into a bit of Utah and then into Nevada and continued on into California," City of Rocks Ranger Sophia Bates said.
As the nation approaches its 250th birthday, Bates considers what happened along this stretch of trail a landmark achievement in American history.
"I would consider it probably in the top 5 — especially for westward expansion. If you're talking about expanding the United States west, it was pretty big," Bates said.
Over the 40-plus years the California Trail was in use, an estimated quarter million people passed through the area.
"Probably around 250,000 people, which is about the size of the population in the city of Boise.... The mass amount of people that came through this trail was during that gold rush time period of 1849 ... the 49ers as they say," Bates said.
For Boise resident Michael Hudson, a regular visitor to City of Rocks, the scale of that pioneer journey is difficult to fully grasp.
"It makes me feel like I'm soft ... could I do what they did? Give up everything, throw it into a wagon with a team of horses or oxen and come thousands of miles for a new life? I'm not sure ... they were hardy folk that we owe a lot to and were standing on their shoulders," Hudson said.
Evidence of that pioneer spirit remains visible throughout the park. At a spot called First Look, visitors can see the same view that greeted wagon trains as they rounded a corner and encountered the basin for the first time.
"You can see this vast basin full of these giant rocks, that they had never seen before ... in their journal entries they commented about this silent city, the City of Rocks," Bates said.
Pioneers used the towering granite formations as a place to rest — and to leave their mark. At Camp Rock, immigrants wrote their names using axle grease, traces of which can still be seen today.
"The darker the name the dirtier the axel grease was," Bates said.
While most of the original California Trail has disappeared, a few locations within the park still show the ruts left by wagon wheels. One of the most striking sites sits on private property at Pinnacle Pass, where grooves carved into the rock tell the story of the difficult descent pioneers faced.
"Pinnacle Pass is an area where the wagons, as they were through the California trail through the City of Rocks and their wagons came through one by one ... this area down here where you see these grooves in the rock here, and kind of along here, it's thought that the grooves were created from ropes or chains that they would have tied to their wagon boxes to prevent it from just rolling down the hill," Bates explained.
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