Abstract: Portable sectionalized flooring suitable for a basketball court or the like is assembled from a plurality of separate floor sections arranged in rows with each section composed of interengaged tongue and groove strips defining the floor surface, spaced stringers extending transversely of such strips and an underlayment interposed between the strips and stringers. Each section has at least one end provided with projecting fingers defined by selected strips projecting beyond strips intermediate to these selected strips for the fingers on adjoining section ends to interdigitate and thereby form interlocking finger joints. Groups of the sections are of different lengths to be assembled in rows with the interlocking finger joints of adjacent rows being staggered and latch devices are provided to interlock adjoining floor sections within each row and adjacent rows within the sectionalized flooring area.