Typically a non-profit theatre supported by local community, whether through donations or taxes.
Actors and technical personnel are usually volunteers from the local community, and perform out of love for theatre.
Community theatres often produce plays with little commercial appeal but high artistic value.
Many community theatres are an excellent training center for people with no prior acting experience. A typical production will cast a combination of experienced actors and those who do not yet have acting experience, but do have talent.
Some community theatres have a full-time professional director (typically college theatres), others use volunteer directors.