Missouri 364 is the Page Avenue Extension, a freeway running west from Interstate 270 at Maryland Heights to I-64 through the St. Charles County suburbs. The numbering corresponds with Interstate 64 to the south, but is otherwise coincidental. No plans are in place to add Missouri 364 to the Interstate Highway system.
The first phase of Highway 364 built was the Veterans Memorial Bridge over the Missouri River, which opened on December 13, 2003.1 East from the Veterans Memorial Bridge to Interstate 270, Highway 364 is officially designated as the “‘Buzz’ Westfall Memorial Highway,” which honors the former St. Louis County Chief Executive who had died before Phase I of the freeway opened.2
The freeway was lengthened west to Mid Rivers Mall Drive in St. Peters on August 30, 2012. Work on the remainder of Missouri 364 west to I-64 at Lake St. Louis commenced in 2013. The roadway opened fully on November 1, 2014.3