It later became defined by the League of Off-Broadway Theatres and Producers as a professional venue in Manhattan with a seating capacity of at least 100, but not more than 499, or a production that appears in such a venue and adheres to related trade union and other contracts.

Previously, regardless of the size of the venue, a theatre was considered a Broadway (rather than off-Broadway) house if it was within the "Broadway Box", extending from 40th Street