Coastal zone managers and researchers often require detailed information regarding emergent marsh vegetation types for modeling habitat capacities and needs of marsh-reliant wildlife (such as waterfowl and alligator). Detailed information on the extent and distribution of marsh vegetation zones throughout the Northern Gulf coast has been historically unavailable. In response, the U.S. Geological Survey, in collaboration with the Gulf Coast Joint Venture, the University of Louisiana-Lafayette, Ducks Unlimited, Inc., and Texas A&M University Kingsville, has produced a classification of marsh vegetation types for Texas, Louisiana, Mississippi, and Alabama. This study incorporates approximately 8,800 ground reference locations collected via helicopter surveys in coastal Texas and Louisiana marsh areas. These data were used for assessing accuracy. Decision-tree analyses using Rulequest See5 were used to classify emergent marsh vegetation types by using these data, multitemporal satellite-based multispectral imagery from 2010, a bare-earth digital elevation model (DEM) based on airborne light detection and ranging (lidar), alternative contemporary land cover classifications, and other spatially explicit variables believed to be important for delineating the extent and distribution of marsh vegetation communities. Image objects were generated from segmentation of high-resolution airborne imagery acquired in 2010 and were used to refine the classification. The overall accuracy corrected for bias, which incorporated true marginal proportions (Congalton and Green, 2009) of the classification, was 90 percent (95 percent CI: 88.0–92.0), and the kappa statistic was 0.81 (95 percent CI: 0.80–0.82) (table 1). The agreement between classification and reference data was significantly greater than zero (z-statistic (Z) = 11.31, p The classification was developed in two phases. The first phase extended from Corpus Christi, Texas to the Sabine River, LA and the second phase extended from the Sabine River, LA to the Alabama/Florida state line. An alternative classification containing only three marsh types was created for coastal Texas, in which, intermediate and brackish marsh were combined into a single class. For more information, please see the U.S. Geological Survey Investigations Report titled "Delineation of Marsh Types of the Texas Coast from Corpus Christi Bay to the Sabine River in 2010." (http://pubs.usgs.gov/sir/2014/5110/).This study provides a more objective and repeatable method for classifying marsh types of the Northern Gulf coast at an extent and greater level of detail than previously available for the study area. The seamless classification produced through this work is now available to help State agencies and landscape-scale conservation partnerships (such as the Gulf Coast Prairie Landscape Conservation Cooperative and the Gulf Coast Joint Venture) to develop and (or) refine conservation plans targeting priority natural resources. Moreover, these data may improve projections of landscape change and serve as a baseline for monitoring future changes resulting from chronic and episodic stressors.