Public queues are those published in the MQIS. All public queues are replicated throughout the enterprise, and can therefore be located by any computer within the enterprise.
Private queues are not published in the MQIS, and therefore do not add to the MQIS replication load. Private queues can be accessed only by applications that have access to the full path or format name of the queue. In the default view, MSMQ Explorer does not display private queues.
For more information on viewing private queues, see MSMQ Explorer Help.