Abstract: In a chromatography column one or more of the end plates defining the column are provided with specially designed lands and grooves to more effectively uniformly distribute the input liquid over the column cross-sectional area and thus improve the separation of sample components, the upper end wall of the column being adjustably positionable to vary the axial length of the column by means of novel structure including readily releasable speed nuts engageable with externally threaded rods, the seal between the movable upper plate and the column wall being so designed as to minimize dead space and thus further increase separating power, and the structure for adjustably positioning said top wall includes elements enabling that structure and the top wall connected thereto to be conveniently supported in inverted condition when separated from the remainder of the column structure.