The Eisenhower–Johnson Memorial Tunnel, a critical passageway beneath the Continental Divide in Colorado, holds a special place in American infrastructure. But is it the longest tunnel in the United States? Let’s delve into the facts, the history, and the engineering behind this remarkable structure to answer that question.

The Eisenhower Tunnel: A Brief Overview

The Eisenhower–Johnson Memorial Tunnel (EJMT) consists of two bores: the Eisenhower Memorial Bore (westbound), completed in 1973, and the Edwin C. Johnson Memorial Bore (eastbound), opened in 1979. Together, they facilitate traffic on Interstate 70, connecting Colorado’s eastern plains to its western slope.

At 1.7 miles (2.73 kilometers) long, the Eisenhower Tunnel was once celebrated as a groundbreaking engineering achievement. It remains the highest vehicular tunnel in North America, sitting at an elevation of over 11,000 feet above sea level. But when it comes to length, there are other contenders for the title of the longest tunnel in the United States.

The Longest Tunnel in the United States

The honor of being the longest tunnel in the U.S. goes to the Delaware Aqueduct in New York, an impressive 85-mile (137-kilometer) tunnel that carries water from upstate reservoirs to New York City. However, this is not a transportation tunnel, so it doesn’t fall within the same category as the Eisenhower Tunnel.

If we narrow the focus to transportation, the Anton Anderson Memorial Tunnel in Alaska claims the title of the longest vehicular tunnel in the United States. This single-lane, 2.5-mile (4.02-kilometer) tunnel connects the town of Whittier to the rest of Alaska’s road system. It surpasses the Eisenhower Tunnel in length, though it operates under vastly different conditions and capacities.

Why the Eisenhower Tunnel Stands Out

While the Eisenhower Tunnel is not the longest, its significance lies in its altitude and usage. Sitting at 11,112 feet, it is the highest vehicular tunnel in North America, presenting unique engineering challenges. Constructing the tunnel required careful planning to manage extreme weather, unstable geology, and the physiological effects of working at high altitude.

Additionally, the tunnel remains one of the most heavily trafficked in the country, with over 12 million vehicles passing through annually. It is a lifeline for commerce and tourism, reducing travel time across the Rockies and providing a safer alternative to Loveland Pass.

Other Notable U.S. Tunnels

For context, here are a few other impressive U.S. tunnels:

1. Hampton Roads Bridge-Tunnel (Virginia): Combining bridge and tunnel sections, this underwater structure spans 3.5 miles (5.6 kilometers).

2. Lincoln Tunnel (New York/New Jersey): This 1.5-mile (2.4-kilometer) underwater tunnel connects Manhattan and New Jersey beneath the Hudson River.

3. Baltimore Harbor Tunnel (Maryland): At 1.45 miles (2.33 kilometers), this tunnel routes traffic under Baltimore’s harbor.

Each has its own unique purpose and engineering marvels, but none match the altitude or strategic importance of the Eisenhower Tunnel.

Conclusion

While the Eisenhower Tunnel isn’t the longest in the United States, it holds its own as a vital and iconic piece of infrastructure. Its high-altitude construction, essential role in Colorado’s transportation network, and stunning location beneath the Continental Divide make it a standout in American engineering history.

So, the next time you drive through this incredible passageway, remember: it’s not just about the length—it’s about the journey. The Eisenhower Tunnel may not be the longest, but it’s undoubtedly one of the most remarkable.