Burrows of the grapsoid crab Ocypode quadrata (Fabricius) are important biogenic sedimentary structures on Texas barrier islands. Variation in the shape, diameter, length, orientation, and areal density of the burrows can be used to define subenvironments of the beach and foredune ridge. An increase in diameter, length, and morphological complexity of the burrows together with a decrease in burrow abundance from the upper foreshore to the back edge of the beach differentiate beach subzones. Greater burrow size and abundance and a simpler shape distinguish O. quadrata burrows in the dune mounds from burrows in the interdune flats of the foredune ridge. A preferred burrow orientation descending to the northwest in the backshore contrasts with a random orientation of burrows in the foredune ridge. Although the preferred orientation is away from the shoreline, factors not directly related to shoreline trend may be responsible.