This study determines the rates of subsidence or uplift in coastal areas of SE Texas by comparing recent GNSS measurements to the original orthometric heights of 340 previously installed National Geodetic Survey (NGS) benchmarks. Understanding subsidence rates in coastal areas of SE Texas is critical when determining its vulnerability to local sea level rise and flooding, as well as for accurate elevation control for flood risk maps. The study area includes major metropolitan and industrial areas as well as more rural areas at risk for flooding and hurricane storm surge. The resurveying methods used in this RTK GNSS study allow a large area to be covered relatively quickly with enough detail to determine subsidence rates that are averaged over several decades, and identify at-risk regions that can be monitored more closely with permanent or campaign-style measurements. Overall, vertical rates vary from -6 to -15 mm/yr subsidence in Port Arthur, Nederland, and other areas of Jefferson County, as well as in areas northwest of Beaumont, Texas. Other areas with subsidence rates between -10 and -4 mm/yr include parts of the Bolivar Peninsula in Galveston County, northeastern Chambers County, and the Mont Belvieu area just east of Houston. Current benchmark elevations were as much as -0.86 m lower than the original, illustrating the need for height modernization surveys in the area. Surprisingly, areas of uplift, with rates as great as +5 mm/yr, were found in some parts of the study area. Several of the counties in the study area are experiencing inundation and erosion from global sea level rise, with local subsidence exacerbating the problem. Many of the counties in the study area were also affected by the storm surge from Hurricane Ike and flooding from Hurricane Harvey. Understanding the current elevation in these areas, as well as the rates of change in elevation, is critical for creating updated flood plain maps and surge inundation models, as well as planning how these maps and models will likely change in the future. Understanding how rapidly the elevations are changing is also critical for planning and maintaining flood and surge protection infrastructure projects such as levees, dune restoration, marsh restoration, and raising of structures to prevent flooding well into the future.