Abstract: A portable floor system includes a plurality of substantially rectangular floor panels adapted for connection along their edges to form an extended floor surface. The extruded edges include complementary tongues and grooves, and complementary locking members for aligning and connecting the edges of the panels. The tongues include notches and the grooves have complementary vertical pins to aid in aligning the panels during locking. The portable floor system has transitional edge trim panels that provide a transition from the floor surface to the underlying supporting surface. The edge trim panels include ribs forming slots for receiving alignment members that provide alignment between the ends of the edge trim panels. The alignment members include set screws and L-shaped members for inserting into complementary ends of corner edge trim panels.