The Rio Grande Valley (RGV), informally called The Valley, is an area located in the southernmost tip of South Texas. It lies along the northern bank of the Rio Grande river, which separates Mexico from the United States. This four-county region is one of the fastest growing places in all of the United States. From having about 325,000 people in 1969, to today a population over 1,300,000 in 2014.Some of the biggest cities in the region are; Brownsville, McAllen, Mission, Edinburg, Pharr, Weslaco, Harlingen, Rio Grande City, and Hidalgo.