The Keystone XL Pipeline will be able to cross through Nebraska.
That decision comes after a vote by the state's Public Service Commission on Monday.
The Keystone system transports crude oil from Canada to Texas, and Keystone would augment other pipelines and complete the entire system.
Monday's vote comes just days after the existing pipeline spilled 210,000 gallons of oil in South Dakota.
The debate over Keystone XL goes back years.
President Trump issued a permit in March approving its construction after former President Obama blocked the project in 2015.
Supporters say it will create jobs, but critics point out that most of those jobs will only last two years.