Riverside Patty, which has been serving oversized burgers to downtown office workers for three decades, closed its Third Street location Wednesday.

Riverside’s website says its landlord has asked it to vacate building and that the Cloverland Avenue location off Siegen Lane remains open for business.

An employee who answered the phone downtown was telling callers that Wednesday was the Third Street restaurant’s last day open and referred calls to the Siegen store, which were unanswered.

The building, known as the Old Louisiana Theater, was built in 1913. The owner, Gordon “Skeet” LeBlanc, could not be reached for comment.

Davis Rhorer, executive director of the Downtown Development District, said Riverside Patty was a well-known downtown institution with a well-deserved reputation among diners in the central business district.