Stream segments, aquatic organism captures, stream surveys, and road-stream crossings described by these metadata accompany a 2012 electrofishing study of the distribution and abundance of aquatic organisms (fish, lampreys, amphibians and crayfish), conducted by the U.S. Geological Survey, and the Pacific Northwest Region Aquatic and Riparian Ecosystem Monitoring Project (AREMP) of the U.S. Forest Service, in the Siuslaw National Forest in western Oregon, USA. The purpose of the study was to quantify the effectiveness of stream-road crossing restoration (culvert replacement to the stream simulation standard) in terms of numbers of fish and length of stream gained through restoration, and to quantify the continuing effects of replaced and non-replaced crossings on the probability of passage by aquatic organisms compared to stream reaches having no road crossing. The sampling design is nested in several ways; sampled stream segments (30-m electrofishing plots) were selected in a spatially balanced random sample within stream networks (contiguous spatial collections of segments within 2 km of a study culvert or road crossing). Networks themselves were randomly sampled for study from the 79 networks in the scope of inference with probability proportional to the length of stream suitable for sampling [< 25% average gradient, < 10 km2 in drainage area, and > 0.283 l.s-1 (0.01 cubic feet per second) in mean annual discharge]. The scope of inference was defined as stream within 2 km of a study crossing (303 stream-road crossings identified as potentially important to salmon and trout based on channel slope, valley bottom morphology, and stream size). At sampled segments electrofishing was used to capture aquatic organisms for identification, counting, and at a sub-sample of sites marking for capture-recapture study. Recapture passes were conducted two days after the initial electrofishing pass.