Systems and methods for intelligently routing an incoming telephone call to an internal extension based on the calling history are provided. According to one embodiment, a session log is maintained by a call monitor of a telephone system. The session log contains multiple call session records relating to telephone calls between internal extension numbers and external telephone numbers. An incoming telephone call from a telephone external to the telephone system is received by the call monitor. The session log is searched by the call monitor for a call session record corresponding to the external telephone number. When a result of the searching meets one or more predetermined or configurable conditions, then a switch of the telephone system is caused by the call monitor to route the incoming telephone call to one of the internal extension numbers.