A liquid container detachably mountable to first and second locking portions of a mounting portion of an apparatus. The liquid container includes a casing for containing liquid and a supply port for supplying the liquid to an ink jet head. At respective first and second sides of the casing, first and second engaging portions are provided, respectively engageable with the first and second locking portions. A supporting member displaceably supports the second engaging portion, and a contact is contactable to a member provided in the mounting portion to permit of display information relating to the liquid container. The supply port is disposed in a third side of the casing which is between the first and second sides, and the contact is disposed at a corner region between the second and third sides.