| Monahans Sandhills | |
|---|---|
 Sandhills at sunrise | |
  Monahans Sandhills  Monahans Sandhills | |
| Location | Ward /Winkler,Texas,United States |
| Nearest city | Monahans |
| Coordinates | 31°38′51″N102°49′23″W / 31.64750°N 102.82306°W /31.64750; -102.82306 |
| Area | 3,840 acres (1,550 ha) |
| Established | 1957 |
| Visitors | 41,285 (in 2022)[1] |
| Governing body | Texas Parks and Wildlife Department |
TheMonahans Sandhills State Park is a 3,840-acre (1,550 ha) state park located in the southernLlano Estacado inWard County andWinkler County, Texas.[2] The closest major town isMonahans, Texas, and the closest limited-access highway ingress is Exit 86 onInterstate 20.
Monahans Sandhills State Park is noted for the presence of sanddunes up to 70 feet (21 m) high. Although desert-like, the Monahans Sandhills are not a desert; they are a part of asemi-arid ecosystem (average annual rainfall 12.3 inches (310 mm)) characterized by the presence of bothgroundwater and relatively nutrient-poor windblownsand. The Shinoak (Quercus havardii) is a local climaxshrub, an unusual type of oak tree which because of local conditions often achieves full growth of only 4 feet (1.2 m) in height. Most of a Shinoak's biomass exists in the form of a lengthy root system reaching down to groundwater. If a Monahans sand dune has become stabilized and has stopped blowing about in the wind, that is often because a small grove of Shinoaks have stabilized the dune with their extensive root systems. Despite the sterility of the landscape, various rodents are relatively common, and several packs of Sandhillscoyotes feed upon them.[3]
Much of the Monahans Sandhills are privately owned property. The state of Texas is operating a 99-year lease with theSealy-Smith Foundation for the ranch on which most of the land of the state park is located; the park opened to the public in 1957, and the state park has leasehold rights to this parcel of the sand hills until 2056.[3]
The Monahans Sandhills are part of thePermian Basin of hydrocarbon formations, and some oil production continues in and around the state park.[3]
Visitors practice several local forms of recreation at the Monahans Sandhills, such assandboarding, 'sand football', 'sand surfing', and sandtobogganing.[3]
The MonahansSandhills consist of a sand deposits 70 miles long and 20 miles wide fromCrane County, Texas toAndrews County, Texas. TheLlano Estacadoescarpment to the east is a barrier to further wind transport ofsediment. The sand probably reached its greatest areal extent in theLate Pleistocene, 16,000 years before the present, with an earlier period of dune building 25,000 years before the present. Thedunes consist of almost purequartz grains with an average diameter of less than 0.22 mm, which is fairly uniform for all of the grains. Dune types include coppice, wind-shadow, Akle,Barchan, andparabolic. Winds from the southeast in the summer, from the northwest in the winter, and the southwest during spring, influence dune shape. These changes in wind directions change the shapes of the dunes and their position, but in general the dunes don't migrate, retaining their position and form when measured year to year.[4]
