In Canada and the United States, port authority (less commonly a port district) is a governmental or quasi-governmental public authority for a special-purpose district usually formed by a legislative body (or bodies) to operate ports and other transportation infrastructure. In Canada, the federal Minister of Transport selects the local chief executive board member and the rest of the board is appointed at the recommendation of port users to the federal Minister; while all Canadian port authorities have a federal or Crown charter called Letters Patent.