By the 1840s, the main route to California followed the California Trail along the Humboldt River in Nevada, then the Truckee River, and finally over the Donner Pass. The name alone, immortalized by the tragedy of 1846-47, hinted at the route's dangers. Northern variations existed, including one pioneered by the Applegate brothers in 1846 that connected to Oregon destinations, and Peter Lassen's variant that passed beneath the peak now bearing his name on the way to Sacramento. But these routes remained long and difficult. When Nobles stumbled onto his easier path, he recognized its commercial potential immediately. After returning to California from his failed gold hunt, he charged a party of businessmen $2,000 to guide them along the new route.

With his paying customers vouching for the route's usefulness, Nobles returned to Minnesota in 1853 to promote his discovery, marrying in Illinois along the way. The Minnesota legislature was sufficiently impressed to commission him to present the route to Congress in Washington. His lobbying proved remarkably successful. Congress appropriated $300,000 for an expedition to survey and improve the trail, led by Frederick W. Lander, who submitted a favorable report in February 1861. The route received an official name befitting its federal backing: the Fort Kearney, South Pass and Honey Lake Wagon Road. Nobles parlayed his success into political office, winning election to the Minnesota Territorial Legislature. He died in St. Paul in 1876, having transformed a failed treasure hunt into a lasting contribution to westward expansion.

The section of trail passing through what is now Lassen Volcanic National Park traverses some of California's most dramatic volcanic terrain. Entering from the northeast corner, the trail skirts the edge of Cinder Cone and the Fantastic Lava Beds, that otherworldly expanse of dark, blocky rock created by eruptions in the 1650s. The path continues past Prospect Peak, crosses Badger Flats, and passes through the Devastated Area, the barren zone created by Lassen Peak's May 22, 1915 eruption. It then parallels the modern Lassen Park Road, threading between Chaos Crags and Table Mountain, crossing Sunflower Flat, and climbing over Nobles Pass. The trail finally exits the park's northwest corner near Manzanita Lake, following the edge of the Chaos Jumbles rock avalanche deposits.

The trail section within Lassen Volcanic National Park was placed on the National Register of Historic Places on October 3, 1975, and is now maintained as a hiking trail. Two California Historical Landmarks commemorate key points along the route. Marker 675 designates a stopping place near present-day Susanville that Nobles established for emigrant parties. Marker 677 marks an earlier moment in the trail's prehistory: the spot where Peter Lassen first glimpsed Honey Lake on October 4, 1850, while still searching for the mythical Gold Lake. The trail remained heavily used until the 1870s, when railroads rendered overland wagon routes obsolete. Today, hikers following the trail through Lassen walk the same path that once carried thousands of hopeful settlers toward California's promises.