Estero Llano Grande State Park, on the southern edge of Weslaco in Hidalgo County, sits at the heart of the Rio Grande Valley. Estero Llano Grande is a small part of the Llano Grande Land Grant that Juan José Hinojosa, chief justice of Reynosa, Tamaulipas, applied for in 1776. It wasn’t until after Juan’s passing in 1778 that the land was officially granted to his family in 1790 by the King Charles IV of Spain.
Estero Llano Grande itself was pieced together in early 2000. An old piece of farm land is now the site of our visitors center and a series of shallow wetlands. An old dried up lake bed that was restored and is now thriving with wildlife is called Alligator Lake because of its inhabitants and its shape. Other parcels include a long term lease agreement with U.S. Fish and Wildlife of the Mercedes Tract, and an addition of Lakeview Trailer Park and a nature trail, now called the Tropical Area and Green Jay Nature Trail, from the city of Weslaco. Those land purchases and contributions along with World Birding Center, Inc. support, and the reclamation of wetland habitat with the help of Ducks Unlimited, allowed for a grand opening in June 2006 with almost 200 acres of park to explore.
Since the grand opening, Estero has grown once more. In the spring of 2010 Estero Llano Grande acquired the Methodist Camp Thicket, now called Camp Thicket, a group retreat facility with prime Thornscrub habitat. Estero Llano Grande is bordered to the south by a section of the Arroyo Colorado watershed, known for many years as Llano Grande Lake, which only adds to the overall wetland appearance of the park. This now puts the park's size at 230 acres of some of the most diverse habitat in the Rio Grande Valley.