The coast-to-coast Interstate 40 runs west–east from the Pacific coast of California at Barstow through Asheville to the Atlantic shores of North Carolina at Wilmington. Interstate 26 runs from Charleston, South Carolina, to Asheville and, partly on a temporary route, continues northwest into Tennessee and the Ohio Valley. There are plans for a $1 billion upgrade and expansion of Interstate 26 in Asheville beginning in 2021. Interstate 240 forms a perimeter around Asheville. U.S. Route 19/23 is an important north and west route. The Blue Ridge Parkway runs northeast from Great Smoky Mountains National Park at Cherokee to Shenandoah National Park in Virginia, passing Asheville and the High Country. U.S. Route 221 runs north to the Virginia border through Blowing Rock and Boone and intersects Interstate 40 at Marion. U.S. Route 321 intersects Interstate 40 at Hickory and heads to Blowing Rock and Boone.