Under Dillon Reservoir, remnants of infrastructure that once ran the old town of Dillon remain, and once in a while the reservoir is low enough to spot some of these pieces of Summit County history, particularly former pieces of road.

Summit Cove resident Steve Johnson said that when he’s driving over Swan Mountain Road, he can sometimes see pieces of the old U.S. Highway 6 and Colorado Highway 9 routes starting to make an appearance, and in mid-December, he decided to get a closer look. He captured a photo of one of the old highways.

“When the lake gets really low, you see it,” Johnson said. “The striping is still visible, which amazes me.”

Historian Sandra Mather wrote her dissertation at the University of Oregon on the geographical history of Summit County and learned endlessly about the history of the reservoir and what was here before it. She said she was amazed to see striping on the roads when they’d show up from below the reservoir in the 1980s.

Mather said these pieces of road are still under the reservoir because nobody went out of their way to bulldoze or move dirt from these locations as the focus was on the old town of Dillon.

“The bulldozers were working around Dillon No. 3, so any roads that were there would have been chewed to bits,” Mather said. “But those there in Summit Cove, and then at the very southern end of the reservoir, and then over by Frisco Marina, the bulldozers weren’t working there like they were working at the old town site, so some of (the roads) survived.”

Today’s Dillon is the fourth iteration of the town. The first two moves were so the town could be closer to railroads, and the third location remained for several decades before plans for Dillon Reservoir moved Dillon to where it is today. Mather said the town was a hub for transportation at this time considering the intersection of two major highways called Dillon home.

A map from the Summit Historical Society shows Summit County sometime in the 1950s, when Dillon was located north of Highway 6, which intersects with Highway 9 before heading west past Frisco toward Vail Pass. This western piece of Highway 6 closely resembles what Interstate 70’s route looks like now.

“That’s why Dillon was so prominent in the county because of the intersection of those two highways,” Mather said. “… And then of course, the railroad came through there — the Denver, South Park (and Pacific) — and that enhanced Dillon’s position as a transportation hub for the county.”

Colorado Department of Transportation spokesperson Elise Thatcher said the road in Johnson’s photo was previously Highway 9. She said when the reservoir was being constructed, 13 miles of the roadway were relocated in addition to 8 miles of transmission line, a hydroelectric plant and a ranger station.

“When Colorado 9 was moved, the section of roadway in the photo was abandoned and that section now runs beneath the reservoir,” Thatcher said.

Denver Water spokesperson Todd Hartman said discussions about alternate routes began in 1956 between officials with Denver Water and the Colorado State Highway Department — CDOT’s predecessor — when it was discovered the intersection of the two major highways was within the planned inundation area.

“In 1958, Denver Water, in discussing shifting the location of the town of Dillon, noted that relocating Highway 6 in a thoughtful way was a critical component to Dillon’s future,” Hartman wrote in an email. “There was discussion on ensuring the new route — though it would probably need to be lengthier to get around the reservoir — would not hinder the space available in town for businesses and residents.”

Hartman said one document shows that Denver Water wanted to emphasize the need to conserve every bit of available space for the new town to provide necessary business, tourist and residential services. This was in an attempt to diminish “wide through travel” rights of way, and the proposed plan from the highway department put Highway 6 along the eastern and northern edges of the community, as it is today.

Alan Rice’s family used to own a ranch on the south side of Highway 6 in what is now the Summit Cove area. The ranch was on the south side of Highway 6, 3 miles east of Old Dillon and about 1 1/2 miles from the Keystone Lodge. Rice said the ranch started about halfway up toward the top of Swan Mountain Road and ran a mile south and west.

Rice said he suspects the road was paved sometime after World War II, but this was done only between Loveland and Vail passes — both passes remained gravel. He said these pieces of road weren’t closed until the reservoir came up high enough to cover them, likely around 1964 or 1965.