As a part of the Barrier Island Comprehensive Monitoring Program (BICM), scientists from the U.S. Geological Survey (USGS) St. Petersburg Coastal and Marine Science Center conducted a nearshore single-beam bathymetry survey along the Chenier Plain, Louisiana from Marsh Island to Sabine Pass. The goal of the BICM program is to provide long-term data on Louisiana's coastline and use this data to plan, design, evaluate, and maintain current and future barrier island restoration projects. The data described in this metadata record will provide baseline bathymetric information for future research investigating island evolution, sediment transport, recent- and long-term geomorphic change and will support modeling of future changes in response to restoration and storm impacts. Over 3,300-line kilometers of single-beam data were acquired during two field missions: USGS Field Activity numbers (FAN) 2017-323-FA, conducted June 2-14, and 2017-324-FA, which occurred July 8-16, 2017 aboard four separate survey vessels. The final x,y,z data are provided in the native World Geodetic System of 1984 (WGS84) G1150 acquisition format (which is equivalent to the International Terrestrial Reference Frame of 2000 [ITRF00]), with values ranging from -26.62 m to -56.83m ellipsoid height, as well as the North American Datum of 1983 (NAD83) reference frame and the North American Vertical Datum of 1988 (NAVD88) GEOID12A , with values ranging from 0.00 to -30.13 m .