Mantua and HWY 89

The history of U.S. Highway 89 (US-89) through Mantua, Utah, is a story of overcoming the geographic isolation of the "Little Copenhagen" valley. Before the highway, Mantua was often cut off from the rest of the state for months at a time due to heavy winter snow.

1. The Pioneer Era (Pre-1924)

Before a major highway existed, the path through the mountains was a steep, dangerous "pioneer route."

• Seasonal Isolation: For nearly 70 years after Mantua was settled in 1863, the road was a summer-only route.

• The Route: Travelers used a direct path by way of Dry Lake to reach Wellsville. In the winter, snow made the climb through Box Elder Canyon (from Brigham City) and Sardine Canyon (to Cache Valley) nearly impassable.

2. The First All-Weather Road (1924–1960)

The transformation of the route began in the early 1920s as part of a push for reliable year-round transportation between Brigham City and Logan.

• The 1924 Construction: A new $200,000 highway was completed in September 1924. This was a "dugway" cut into the mountain with a maximum grade of 6%, making it the first "all-weather" road into the valley.

• The "True" Sardine Canyon: The 1924 alignment actually went through what is geographically known as Sardine Canyon. If you look northeast from the modern highway near the summit today, you can still see remnants of this old road winding along the hillside.

• Official Designation: When the U.S. Highway system was created in 1926, this route became part of US-89 (and later US-91).

3. The Modern Alignment (1960–Present)

As vehicle traffic increased and the road became a primary route to Yellowstone National Park, the 1924 road became too narrow and winding for modern speeds.

• The 1960 Bypass: To streamline the drive, a new alignment was built in 1960. This version—the one we use today—bypassed the actual Sardine Canyon entirely.

• Nomenclature Confusion: Even though the modern highway actually travels through Wellsville Canyon and Dry Canyon, locals almost universally refer to the entire stretch from Mantua to Wellsville as "Sardine Canyon."

• Safety Upgrades: Over the decades, the road has been widened to four lanes with a concrete divider to combat the "treacherous" reputation the canyon earned during winter storms.

Sources:

• Utah Department of Transportation (UDOT) (SR-89)

• U.S. Geological Survey (USHS)

• Municipal & County History

• County Archives: Historical surveys from 1914

• The Box Elder News: Historical newspaper archives from August 1924

• Utah State University (USU) Digital Exhibits

• The Mystery of Utah History

• Division of Archives and Records Service