Abstract: A lockable post assembly includes a post member (12) having a vertical axis and an anchor portion (14) at a lower first end thereof. The anchor portion (14) has a head (16) and neck (18), the neck (18) defining a female constriction above the head (16). An anchor socket (22) secured within the ground is adapted to lockably receive the anchor portion (14) so as to hold the post member (12) upright. The anchor socket (22) has a keyed passageway (24) with an inward collar portion (26). The collar portion (26) defines a male constriction above a lower cavity (30). In use, the anchor socket (22) lockably receives the anchor portion (14) by the steps of inserting the anchor portion downwardly in a first orientation about the vertical axis so that the head (16) enters the lower cavity (30), and then rotating the anchor portion (14) to a second orientation about the vertical axis so that the head (16) is underneath or abuts a bottom surface of the collar portion (26).