On Thursday, Maryland officials gave Elon Musk’s Boring Company permission to dig a 10.1-mile tunnel “beneath the state-owned portion of the Baltimore-Washington Parkway, between the Baltimore city line and Maryland 175 in Hanover,” according to the Baltimore Sun.

According to Maryland Transportation Secretary Pete Rahn, The Boring Company (which Tesla and SpaceX CEO Musk founded to advance tunneling technology) wants to build two 35-mile tunnels between Baltimore and Washington, DC. The federal government owns about two-thirds of the land that Musk’s company would need to dig underneath. As of Friday, it was unclear whether that permission had been granted. (A Department of Transportation spokeswoman told Ars that the land in question was owned by the National Park Service, which did not immediately respond to request for comment.)

But the 10 miles that have been approved by the state of Maryland will for the first leg of an underground system that could contain a Hyperloop system. Musk first floated the idea of a Hyperloop—which would ferry passengers through a low-pressure tube in levitating pods floating above a track using air-bearings—in 2013. But the CEO determined that he didn’t have time to see his idea through to fruition, so he issued a white paper and challenged startups and students alike to make headway on the concept.

Musk seems to have changed his mind about not building his own Hyperloop though. In July, Musk tweeted that he had received “verbal govt approval for The Boring Company to build an underground NY-Phil-Balt-DC Hyperloop.” Musk added that the infrastructure would allow people to go from New York to DC in 29 minutes.

Such a project would cost billions of dollars, the Baltimore Sun noted, adding “The state does not plan to contribute to the cost of the project.”

The Maryland Transportation Authority told the Sun that The Boring Company had been given permits similar to those a utility gets to install underground infrastructure.

According to the Washington Post, Maryland Governor Larry Hogan said he was proud “to support The Boring Company to bring rapid electric transportation to MD – connecting Baltimore City to DC.”

Ars reached out to The Boring Company, and a spokesperson there declined to comment beyond a statement found in Maryland’s press release. “The Boring Company would like to thank Maryland, Washington DC, and the White House Office of American Innovation for their support,” the company said. The Washington Post noted that, “In March, President Trump appointed his son in law, senior adviser Jared Kushner, to lead the office," although it's still unclear what support the Office of American Innovation contributed.