SACATOSA CREEK. Sacatosa (Zacatosa) Creek rises three miles northwest of Farm Road 2523 in southeastern Val Verde County (at 29°28' N, 100°46' W) and runs southeast twenty-one miles to its mouth on Sycamore Creek, one mile before that stream meets the Rio Grande (at 29°15' N, 100°00' W). Its course crosses steep to gentle slopes and flat terrain on limestone, shale, siltstone, and inactive wash deposits of sand and gravel. Generally dark, calcareous stony clays and clay loams support scrub brush, water-tolerant hardwoods and conifers, grasses, and mesquites.