Abstract: A wall start panel for knock-down portable partition systems of the type having a plurality of panels, each having standard width posts interconnected by structural members in a spaced-apart relationship to define a standard panel width. The wall start panel includes at least one structural member and a standard width post having a unitary construction and including a connection port. The standard width post also has opposite side faces defining a standard post width therebetween. The wall start panel further includes a wall start post having a connection port and having opposite side faces defining a width therebetween substantially less than the standard post width. The structural member spans between and releasably interconnects the standard width and wall start posts in a spaced-apart relationship. The wall start panel has a substantially standard panel width, such that the wall start post can be secured to an existing wall without use of a trim piece to close off the wall start panel.