Metro Transit is an enterprise of the Bi-State Development Agency and operates public transportation services in the St. Louis region. In 2023, the system had an annual ridership of 19,528,200, or about 59,800 per weekday as of the fourth quarter of 2023.

The Bi-State Development Agency was established as an interstate compact between Missouri and Illinois in 1949. This compact created an organization that has broad powers in seven county-level jurisdictions. Bi-State operates five enterprises including the Gateway Arch Riverfront, Metro Transit, the St. Louis Downtown Airport, the St. Louis Regional Freightway and the Bi-State Development Research Institute.