The Southwest corridor extends from the City of St. Louis  to southwest St. Louis County near the Meramec River.

A 1991 Systems Analysis prioritized the Southwest corridor as a Tier III priority. However, since the 1991 analysis, no further planning, involving possible MetroLink extensions, has occurred foron the Southwest corridor.

In order to build any future MetroLink extension, federal funds will be needed along with a significant local match. To be considered for federal funding, specific guidelines need to be followed. One federal requirement is to conduct a planning study assessing needs,  analyzes alternatives and evaluatesminimizes impacts. Click here to see a chart of the complete federally mandated planning process. This part of the process has not yet been carried out for the Southwest corridor.