Devices and systems for navigation and positioning a central venous catheter within a patient. In an exemplary embodiment of a system of the present disclosure, the system comprises a first pole and a second pole, the first pole and the second pole configured to generate an electric field within a mammalian body sufficient to obtain a plurality of field measurements therein, and an elongated body configured for at least partial insertion into a blood vessel of the mammalian body and advancement through a vasculature, said advancement dependent upon the plurality of field measurements indicative of one or more locations of a portion of the elongated body within the vasculature. In at least one embodiment, the elongated body is configured as a stylet.