Herd of Bison (Bison bison) Hayden Valley Yellowstone National Park Wyoming USA. (Photo by: Avalon/Universal Images Group via Getty Images)
CNN  — 

As US states gradually ease restrictions, access is also opening up at the country’s vast national parks.

Yellowstone National Park said Wednesday it will begin to reopen on a limited basis on May 18, almost two months after it closed to visitors, a statement from the National Park Service says.

The park, which covers 3,472 square miles in Wyoming, Montana and Idaho, has been closed to visitors since March 24 due to the Covid-19 pandemic.

Grand Canyon National Park in Arizona also announced a partial reopening on Wednesday. Grand Canyon National Park’s South Rim South Entrance will reopen May 15-18.

The entrance will be open to incoming traffic from 6 to 10 a.m. for daytime access to certain viewpoints, picnic areas and restrooms.

The South Rim’s East Entrance and Desert View area will remain closed as will Grand Canyon Village and a number of trails.

At Yellowstone, a three-phased plan has been released that initially opens the South and East entrances in Wyoming and limits visitor travel to the lower loop of the park. The first phase will allow visitors to visit Yellowstone Lake, Old Faithful and Canyon Village as well as restrooms, self-service gas stations, trails and boardwalks in open parts of the park.

Yellowstone entrances on the Montana border will remain closed for now as will campsites and overnight accommodations. The park is also not allowing commercial tour buses back in or opening hotels and dining establishments.

Offerings such as campgrounds and hotels are part of the second and third phases of Yellowstone’s reopening plan.

The park says it has developed “a range of mitigation actions” to guard against Covid-19, including protective barriers where needed, encouraging the use of face masks in high-density areas, metering visitor access in certain locations and increasing cleaning frequency of facilities.

Wyoming “requested the state’s entrances open the week of May 18,” according to the statement.

“Montana and Idaho continue to have out-of-state restrictions in place and the park is working closely with these states and counties to open the remaining three entrances as soon as possible.”

Grand Teton National Park in Wyoming and Zion National Park in Utah are among other National Park Service sites that have recently announced plans to reopen in stages.