The U.S. Geological Survey (USGS) 3D Elevation Program (3DEP) has initiated the development of a second pilot 3D National Topography Model (3DNTM) to generate 3-dimensional surface elevation models that integrate topographic bare-earth elevation surfaces with river channel bed and coastal bathymetry and topobathymetry. Detailed knowledge of integrated river system topography, bathymetry, and topobathymetry is essential for fisheries habitat restoration, hydrologic modeling, and other key science applications such as flood mapping and identification of fluvial geomorphic features. An integrated 1-meter topobathymetric digital elevation model (TBDEM) for Hardin, Orange, and Jefferson counties in Southeast Texas has been developed for this second pilot study. This pilot 3DNTM product supports the Southeast Texas Flood Coordination Study where flood planning and modeling are essential for resource management to minimize impacts from rainstorm and hurricane events. Within the pilot project area of interest, the following hydrographic features are included: reaches of the Neches and Sabine Rivers, Sabine-Neches Water Way (Sabine Channel), Lake Sabine, the Keith Lake-Salt Bayou, and the Intercoastal Waterway. The Southeast Texas TBDEM comprises the spatial integration of 12 different geospatial elevation sources, including topographic lidar data from USGS 3DEP and Texas Strategic Mapping (StratMap), single-beam acoustic data from Texas Water Development Board for the Keith-Lakes-Salt Bayou System, multiple single-beam acoustic surveys from the U.S. Army Corps of Engineers, and nearshore to offshore bathymetry from the National Oceanic and Atmospheric Administration (NOAA), National Centers for Environmental Information (NCEI). The integrated TBDEM will provide a fundamental geospatial baseline to support enhanced 2D/3D hydrologic, storm surge, and sediment-transport modeling. Geospatial data were integrated where the best available topography, topobathymetry, and bathymetry elevation data are sorted and prioritized based on survey date, accuracy, spatial distribution, and point density to develop a TBDEM. Every input data source in the TBDEM has been horizontally referenced to UTM Zone 15 N, NAD83 2011 and vertically referenced to the North American Vertical Datum of 1988 (NAVD88) Geoid12b. The spatial resolution is 1 meter with general elevations ranging from 100.05 meters on land to -34.43 meters offshore. The overall temporal range of the input topography, topobathymetry, and bathymetry is 1933 to 2021.