Route 364, known locally as the Page Extension, the Page Avenue Freeway, the Page Expressway, or simply the Extension, is a freeway that connects St. Louis County in Maryland Heights with St. Charles County in Lake St. Louis via the Veterans Memorial Bridge over the Missouri River. The highway is a designated auxiliary state route of I-64. Route description Missouri Route 364 runs roughly 21 miles through suburban St. Louis and St. Charles Counties. Its western terminus is an interchange with Interstate 64, U.S. Routes 40 and 61, and Route N in Lake St. Louis, and its eastern terminus is an interchange with Interstate 270 and Route D, which carries Page Avenue east into St. Louis. Construction progressed west throughout the 2000s and early 2010s, with two changes to the western terminus of the route. The first phase of construction was completed with a western terminus at Route 94 in St. Charles; the freeway opened to traffic on December 14, 2003. In 2012, upgrades to the Route 94 corridor were completed, and Route 364 was signed with Route 94 on a 5-mile concurrency; the western terminus was moved to the intersection at Mid Rivers Mall Drive and Pitman Hill Road. The final section of freeway northwest of Route 94 was opened to traffic on November 2, 2014, carrying the freeway to its final western terminus at I-64, U.S. 40, U.S. 61 and Route N in Lake St. Louis. Missouri Route 364 serves as an alternate route of Interstate 64 to Interstate 270 through the rapidly developing suburbs in St. Charles County and western St. Louis County. Its designation as Route 364 indicates that it is an auxiliary route of Interstate 64, however there are no current plans to give the highway an interstate designation despite the fact that the entire route was constructed to interstate standards. Interstate 64 to Route 94 Route 364 begins at a cloverleaf interchange in Lake St. Louis with I-64, U.S. 40, U.S. 61 and Route N. From this point until Route 94, Route 364 is a semi-rural freeway with two lanes in each direction with a wide, grassy median between the carriageways. From I-64, the freeway turns east-southeast into Dardenne Prairie and has another interchange with Route N. From that intersection, the highway continues southeast for two miles and has a SPUI Interchange with Route K. The highway then continues through several miles of undeveloped