SIOUX FALLS, S.D. (KELO) — South Dakota’s longest state highway still has about 3 1/2 miles of gravel surface.

South Dakota Highway 20 stretches 386.983 miles from the border with Montana not far from Camp Crook, across the state to the border with Minnesota near Revillo, according to the South Dakota Department of Transportation.

“It is still gravel,” Harding County Highway Superintendent Jeremy Humhacht said of the 3 1/2 mile section east of the Montana border. “The state just re-graveled it,” he said.

“Pretty much everyone is used to it. It’s been that way for years,” Humhacht said.

South Dakota Highway 20 across South Dakota. From Camp Crook to Revillo.

SD Highway 20 is more than three miles of gravel.

“There’s a lot of neat sights to see,” said Collette Tifft, who owns the Reva Store with her husband Vince. “There’s a lot of critters and every once in a while, you may see an elk. There’s a lot of wildlife.”

SD Highway 20 also passes through the Custer National Forest.

The highway crosses the James River on the east side as it heads into Conde, Bradley, and eventually, Watertown.

The state highway is not the longest stretch of road in the state. That designation belongs to the 444.19 miles of U.S. Highway 18 in the state, according to the SD DOT.

The highway’s route in the state ends near Edgemont on the western side of the state and at Canton on the eastern side of the state.

“The first cement by Canton was in 1930,” local resident Omar Peterson said of U.S. Highway 18.

U.S. Highway 18 was announced in 1927 as part of the numbered highway system for roads as continuous routes across the U.S., according to American Highways in April 1927. American Highways was published by the American Association of State Highway Officials.

“For the past two years the State highway departments of the Nation have been working on a plan, in cooperation with the Department of Agriculture, of designating certain through roads with numbers that would be carried continuous from coast to coast,” American Highways said.

Peterson has seen changes in U.S. 18 by Canton in his 88 years of living in the town. He was on the Lincoln County Board of Commissioners from the mid-1970s until the 1980s. He recalled a 1980 letter from the head of the SDDOT that talked about a bypass around Canton.

“I was never for a bypass,” Peterson said. The highway passes through the middle of Canton including by the county courthouse. The town benefits from the highway running through it.

“You’ve got traffic, you’ve got people, you’ve got buyers,” Peterson said.

A bypass would likely have taken the highway north of town over the Big Sioux River, he said. That would have been an expensive and inefficient project, Peterson said.

The most recent project for U.S. Highway 18 is an eight-mile section from Interstate 29 west toward Canton. The SD DOT will convert the two-lane section to a four-lane divided highway. The SD DOT cited increased traffic volumes as the reason.

Aaron Eberle is on the opposite end of U.S. Highway 18. Eberle has used Highway 18 for several years on a commute to work in Hot Springs. Eberle also takes the highway on the way to visit family in Lusk, Wyoming.

Highway 18 area at Mule Creek Junction, Wyoming, is a path in and out of South Dakota, Eberle said.

“I see a lot of Colorado traffic,” Eberle said of the Mule Creek Junction path.

Eberle likes the trees and hills of the landscape of Highway 18 in the region, but, “it’s always a relief to come over the hill home to Edgemont.”

Interstate 90 was part of the Federal Aid Highway Act of 1956. This act provided a way to pay for a proposed interstate highway system that had been proposed in the 1944 act, according to the History Channel.

Interstate 90 in South Dakota. Mileage is less on the map because the coordinates are not at state borders.

Interstate 90 is one of only three interstate highways that run across the entire country. It is also the longest at just over 3,000 miles. I-90 is 412.73 miles in South Dakota, which makes it the longest interstate, according to the SD DOT.

I-90 was completed in 1976.

Not as fast as the interstate but worth the slower pace

Peterson said he’s traveled U.S. Highway 18 west from Canton multiple times, including several trips across the state.

“Mostly 18 is a fun road now,” Peterson said. The highway passes over the Missouri River near Pickstown. There is prairie land on either side of the state, he said.

U.S. Highway 18 map. Mileage is not complete as the coordinates are not from border to border.

Drivers use the highway to get to vacation spots or to take a more leisurely trip around the state, he said.

The Reva Store is about 25 miles from the North Dakota border, Tifft said.

“There is quite a bit of traffic,” Tifft said. The store sits between Buffalo to the west and Bison to the east. “It’s like an oasis that pops out of nowhere,” Tifft said about her store.

But, Tifft will also point out that ‘nowhere’ is still busy. Tourists will often say they didn’t know the store was there but are thankful it was as they needed gas, she said.

Locals depend on the store for staples including feed and vaccines for livestock.

A U.S. Forest Service photo of the Sioux Ranger District which has its office in Camp Crook.

The western region around SD Highway 20 includes Slim Buttes which is one of the larger eight land units on the Sioux Ranger District, near Buffalo.

The area that includes Reva is a popular hunting region.

“Hunting season has started up so there are a lot of hunters,” Humbracht said. “There’s quite a bit of traffic during the last three to four months of the year.”

Tifft said some of the seasonal hunters are regulars at the store each year.

As summer will turn into fall and fall into winter, the best traveling days on the long roads could eventually be hampered by the weather.

Winter can make the drive longer on Highway 20, Tiffte said.

Just as it can on Highway 18, Eberle said.