Examples of the present disclosure provide a computing device expansion system. According to one implementation, a docking receptacle is coupled to a touch-enabled monitor computing device and is also configured to receive and connect to a portable electronic device. Furthermore, when the portable electronic device is attached to the docking receptacle, a display area of the portable electronic device is cloned on the monitor computing device such that touch input on either the portable electronic device or monitor computing device is replicated on the monitor computing device or portable electronic device.