What is the wide stretch of land east of the sierra madre oriental?

The wide stretch of land east of the Sierra Madre Oriental is primarily composed of the Gulf Coastal Plain, which extends along the eastern side of Mexico. This region features a mix of flat lands and rolling hills, characterized by a subtropical climate and diverse ecosystems. It includes various states, such as Tamaulipas, Veracruz, and parts of San Luis Potosí, and is significant for agriculture and oil production. The area also encompasses important rivers and wetlands that contribute to its ecological diversity.