Arizona Department of Transportation

Sign marking the future Interstate 11 corridor.

A group of conservationists has filed suit to challenge the Federal Highway Administration’s approval of Interstate 11, from Nogales to northern Arizona.

The freeway would run past national monuments, wilderness areas and other undeveloped lands.

The areas affected include Saguaro National Monument and Ironwood Forest National Monument.

Conservationists say it would disrupt wildlife corridors and could harm endangered species. Carolyn Campbell is with the Coalition for Sonoran Desert Protection.

She says the Pima County Board of Supervisors, city of Tucson and a number of local residents have opposed the project.

“There were two public hearings in Tucson during the development of the environmental impact statement," Campbell said. "There was one in the downtown convention center. There were hundreds of people there. Not one person spoke in favor of it.”

The Department of Interior wrote the agency and said that Bureau of Reclamation, National Park Service and Fish and Wildlife Service have also expressed concerns about the project.

The suit maintains that the agency sidestepped environmental review before giving its approval.