First stretch of Interstate 11 opens, bypassing Boulder City Mick Akers, Las Vegas Sun · August 9, 2018 at 8:41 pm The first major addition to the federal interstate system since 1992, the opening of the initial stretch of Interstate 11 was touted today as the beginning of a larger story. The $315 million project between Hoover Dam and Henderson finished two months ahead of schedule.The Nevada Department of Transportation and the Regional Transportation Commission of Southern Nevada worked on the 15-mile stretch. “This just shows you what can be done when everyone comes together,” said U.S. Sen. Catherine Cortez Masto, D-Nev. Ultimately, I-11 is expected to connect Canada and Mexico. Before that, it will link the two largest cities not connected by an interstate — Las Vegas and Phoenix.