Construction on the US 340 freeway east toward Frederick began in 1966. The freeway east to the current Point of Rocks – Jefferson segment of US 15 was completed in 1967; however, the US 15 interchange would not become operational until the new US 15 was completed and the two U.S. highways became concurrent in 1970. US 340's interchanges with I-70 and MD 180 were completed in 1968 and the portion of the freeway from the US 15 interchange east to MD 180 opened in 1969. At that time, MD 180 was extended east over the old Jefferson–Frederick section of US 340. US 340's interchanges with MD 67 in Weverton and Mt. Zion Road near Frederick opened in 1971 and 1972, respectively. Several ramps were added to improve access between US 340 and I-70 in 1997, including a pair of ramps from eastbound I-70 to US 340 and the connection from northbound US 340 to westbound I-70 at US 340's northern terminus. The interchange at US 340's northern terminus was converted from a cloverleaf interchange to a partial cloverleaf interchange with traffic signals in 2004.