The Rio Grande Delta in Texas and Tamaulipas is a significant geologic system that formed between 8000 and 3000 years ago. The delta was created by a sediment-loaded Rio Grande during a dry period. Today, the delta is inactive due to upstream reservoirs built since the 1940s. The delta's landforms are influenced by wind and erosion processes, creating unique clay dune deposits and hills. The delta has been transgressed by barrier systems since 3000 years ago. The Pleistocene deltas underlying certain cities likely have similar features.