The main river in the state of Texas is the Rio Grande. This river flows approximately 3,051 kilometers (1,896 miles) and forms part of the border between the United States and Mexico. The Rio Grande is significant for providing water for agriculture, drinking, and industry in both countries. It supports diverse ecosystems along its banks and is a crucial source for recreational activities such as fishing and rafting. Additionally, the Rio Grande has historical importance, having served as a boundary for early exploration and settlement in the region.