The Los Angeles Metropolitan Transit Authority (sometimes referred to as LAMTA or MTA I) was a public agency formed in 1951.

Originally tasked with planning for rapid transit in Los Angeles, California, the agency would come to operate the vestiges of defunct private transit companies in the city.

Formed in 1951,[1][2] LAMTA's original mandate was to do a feasibility study for a monorail line which would have connected Long Beach with the Panorama City district in the San Fernando Valley via Downtown Los Angeles.

The agency's powers were expanded in 1954, authorizing it to study and propose an extensive regional transit system.

[5] The MTA began operating the lines on March 3, 1958,[6] and continued to do so until the agency was taken over by the Southern California Rapid Transit District on November 5, 1964.