A proposal for a major highway construction project through the heart of a national park isn't usually cause for rejoicing by park supporters, but that was the case nearly 40 years ago at Cumberland Gap National Historical Park. An upcoming event at the park will celebrate the Cumberland Gap Highway Tunnel, which was finally completed in 1996.

The Cumberland Gap, on the Kentucky-Tennessee border, was an important travel route long before Europeans came to North America.  In centuries past, it was a game trail used by both the Shawnee and the Cherokee; by the 1750s, English speakers began referring to the trail as the Warrior's Path.

In the late 1700s the trail became part of the Wilderness Road, a key passage for pioneers flooding into the then-wilderness of Kentucky. Historians estimate that by the early 1820s, several hundred thousand people traveled this historic "gap" through the mountains.

The area's rich history eventually led to the establishment of Cumberland Gap National Historical Park. Authorized in 1940, the park was finally dedicated in 1959. The area's advantages as a route through the mountains hadn't changed, however, and the former Wilderness Road had undergone major changes long before the park arrived on the scene.

In 1908, a demonstration project by the Bureau of Public Roads resulted in the construction of a "2.5 mile ribbon of crushed, compacted, and rolled limestone highway through Cumberland Mountain to link the towns of Middlesboro, Kentucky, and Cumberland Gap, Tennessee."

By the time the park was established, the former Wilderness Road had long since disappeared under U.S. Highway 25E. As traffic—and accidents—continued to grow on the winding mountain road, it acquired yet another, more sinister, nickname: "Massacre Mountain."

In what may seem an unlikely alliance, historians, park boosters and highway engineers joined forces to push for a major construction project in the park to reroute the highway via a tunnel under, rather than over, the historic Cumberland Gap.

The idea began to gain traction in 1973 with the signing of a law directing the National Park Service to construct tunnels through Cumberland Mountain in order to remove traffic from the historic corridor.

According to the current park superintendent, Mark Woods, two objectives were detailed in the legislation: restore the historic appearance of the Gap and Wilderness Road and improve traffic safety for motorists.

It would prove to be a monumental—and lengthy—task.

Through a combined planning, design, and construction effort led by the National Park Service and the Federal Highway Administration, the project would ultimately cost $265 million and include rerouting two U.S. highways; twin 4,600-foot tunnels; five miles of new 4-lane approaches to the tunnels; two highway interchanges; seven roadway bridges (four in Kentucky and three in Tennessee); a 200-foot railroad bridge; two pedestrian bridges on hiking trails; and, four new parking areas inside the park. A railroad tunnel that was abandoned as part of the project was repaired and reused to house numerous utilities and serve as a part of a greenway trail system.

Project design work started in 1979 and actual construction began in 1985 on a pilot tunnel that was 10 feet wide, 10 feet high, and 4,100 feet long, drilled from both sides of the mountain. The pilot tunnel took two years to drill, but proved to be invaluable in the successful completion of the work.

The pilot tunnels revealed the geologic and hydrologic challenges facing the project, including springs that would produce 450 gallons of water every minute regardless of the weather, voids with thick clay infills, caverns as tall as 85 feet, and a lake of water 30 feet deep.

To keep the tunnels dry, each is lined with a waterproof PVC membrane that is covered with a 10-inch-thick concrete lining. Groundwater drains into a stream that empties into Little Yellow Creek within the park. Water from the caverns flows through a 5-foot-diameter steel pipe under the roadway and into the cavern on the opposite side of the tunnel. During construction, daily water quality monitoring was required; today, water flow is monitored in the tunnel's Kentucky control room.

With the opening of the tunnels to traffic in October 1996, the dangerous section of U.S. Highway 25E was closed to the more than 18,000 vehicles that passed through the historic park on a average day. Today, the tunnels carry more than 11 million vehicles annually, or approximately 32,000 per day.

Superintendent Woods notes that the opening of the Cumberland Gap Highway Tunnel on October 18th, 1996, forever changed the face of Cumberland Gap National Historical Park. The asphalt and the traffic are gone from the historic Cumberland Gap. All that remains is a six-foot-wide trail—not all that different from the one known by Daniel Boone.

"Visitors to Cumberland Gap National Historical Park are now able to walk in the footsteps of Colonel Boone himself and the nearly 300,000 pioneers who journeyed through the nation's first doorway to the west," Superintendent Woods says.

Woods also acknowledges "the incredible relationship which the national park has with the states of Kentucky and Tennessee in the operation of the tunnel. While the National Park Service owns the tunnel, we've turned the operation over to Kentucky and Tennessee; their diligence has made for safe passage for millions of travelers. We also commend Tunnel Manager John Burke and the tunnel staff. Due to the cleanliness of the tunnel and its impeccable upkeep, park visitors, almost daily, comment that they thought the tunnel was recently built."

Frequently walking the restored trail through the Cumberland Gap, Superintendent Woods recounts that his most cherished walk was with Dr. Thomas Clark, historian laureate of the Commonwealth of Kentucky, several years before Clark's death. Dr. Clark had identified the Gap as one of 11 sites within the Commonwealth that every Kentuckian should visit.

"Dr. Clark expressed to me that his dream was to walk in the Gap in the footsteps of Boone and in the absence of any vehicle traffic. Dr. Clark's dream came true and so too did the 60-year old dream of the National Park Service and Congress. I can only imagine a hundred years from now when our descendents are walking through the Gap in our footsteps. History continues to unfold in the nation's first doorway to the west. The Cumberland Gap Tunnel and Gap restoration stories are truly ones to behold."

A reception at the park's park visitor center on October 18th, 2011, will celebrate the 15th anniversary of the opening of the tunnel. The event will showcase the tunnel's motto, "Drive into the Future, Restore the Past," and will include photo exhibits, the showing of the film, "The Cumberland Gap Tunnel," and historical re-enactors mingling with park visitors. The reception will be from 11 a.m. to 1 p.m. and is open to the public.

Information on the reception, which is being co-hosted by the Cumberland Gap Tunnel Authority and the Bell County (KY) Chamber of Commerce, is available by calling the park visitor center at 606-248-2817, extension 1075.

Driving directions and information about Cumberland Gap National Historical Park are available on the park website.