BOISE, Idaho — A bill designating a swath of pristine Idaho backcountry named in honor of 19th century Hawaiian trappers as federally protected wilderness will be introduced this week in Congress, sponsor U.S. Sen. Mike Crapo said.

The Idaho Republican's proposal would preserve more than a half-million acres of high desert plateaus, yawning river gorges and rocky hill country in the remote Owyhee region of Idaho's southwestern corner, one of the most biologically rich and sparsely populated regions left in the western United States.

The name Owyhee, which graces a river, desert and mountain range in the region, comes from Pacific explorer Captain Cook's spelling of Hawai'i and honors the Hawaiian trappers who ventured into the uncharted region southwest of Boise in 1818 and were never seen again.

The proposal also would close off about 100 miles of old roads, protect nearly 400 miles of the Owyhee, Jarbidge and Bruneau waterways and open up some 200,000 acres of public lands previously off-limits to all-terrain-vehicles and ranchers.

Some conservationists say the proposal would open up too much potential wilderness to development. But John Robison of the Idaho Conservation League said the compromises environmentalists made with ranchers, off-roaders and other interest groups are worth the protection of some of the most spectacular scenery in the state.