San Idelfonso Creek is a small stream of water located in Webb County, Texas which runs through Laredo, Texas. The creek is formed within east Laredo and runs southwest for 8 miles until connecting to the Rio Grande. San Ildefonso Creek was dammed in east Laredo to form San Ildefonso Creek Lake, the second largest Lake in Laredo. The terrain surrounding the creek is mostly clay and sandy loams. The vegetation surrounding the creek is mostly made up of mesquite, cacti, chaparral, hardwoods and grasses.