PORT PHILIP, a large bay of Australia, in the colony of Victoria, about 35 miles in length and as much in breadth, with an entrance not quite 2 miles wide; S. Lat. (of Point Nepean at the entrance) 38. 18., E. Long. 144. 42. On its west side is an inlet, at the head of which the town of Geelong stands; and at its northern extremity the Yarra-Yarra flows into Port Philip, having Melbourne on its banks about 8 miles up. (See MELBOURNE.)