Sen. Tim Johnson says he has introduced a bill to move ahead with creation of a visitor center at the Minuteman Missile National Historic Site in western South Dakota.

In a release, the senator says his measure would transfer 25 acres of National Forest Service land to the National Park Service to build the visitor center.

Legislation in 1999 required that two sites be evaluated as potential locations for a visitor center. The new bill to adjust the boundary would allow for the construction of a visitor center and administrative facility at Exit 131 off Interstate 90.

Johnson says visits to the site have grown from fewer than 5,000 people in 2004 to more 30,000 people last year.

He says he helped establish the site in the National Park system 10 years ago and that he's glad he can follow through on fully developing resources for visitors.