PORTLAND, Ore. — Members of the Confederated Tribes of Warm Springs have approved a plan to build a facility to grow marijuana on their reservation in central Oregon and to sell it at tribe-owned stores outside the reservation.

The tribes are among the first in the country to enter the marijuana-growing business, a year after a Department of Justice policy indicated tribes could grow and sell marijuana under the same guidelines as states that opt to legalize.

Tribal officials said more than 80 percent of tribal voters favored the proposal in the referendum, which was held Thursday.

Warm Springs’s plan is to build a 36,000-square-foot greenhouse to grow and process the cannabis. Officials expect the project will create more than 80 jobs. Annual net revenue from the three proposed tribe-owned retail shops would top $26 million, the officials estimated.