| Sentinel Mesa | |
| Elevation Ft: | 6450. |
| Elevation Ref: | [1] |
| Prominence Ft: | 920. |
| Prominence Ref: | [2] |
| Isolation Mi: | 2.64 |
| Parent Peak: | Mitchell Mesa (6,586 ft) |
| Map: | Utah#USA |
| Map Size: | 230 |
| Label Position: | top |
| Location: | Navajo Reservation San Juan County, Utah, U.S. |
| Range: | Colorado Plateau[3] |
| Coordinates: | 37.0113°N -110.1044°W |
| Topo: | USGS Monument Pass |
| Rock: | Sandstone |
| Type: | Mesa |
| Easiest Route: | climbing |
Sentinel Mesa is a 6450feet summit in San Juan County, Utah, United States.[1] It is situated 1.5miles north of the Monument Valley visitor center on Navajo Nation land and can be seen from Highway 163. The mesa is immediately northwest of the iconic West and East Mitten Buttes. The nearest higher neighbor is Brighams Tomb, to the north-northeast.[2] Precipitation runoff from this mesa's west slope drains to Mitchell Butte Wash, whereas the east slope drains to West Gypsum Creek, which are both part of the San Juan River drainage basin.[3] The "Sentinel" name refers to how the mesa oversees Monument Valley which the Navajo consider as one of the "door posts" to Monument Valley.[4] The landform's toponym has been officially adopted by the U.S. Board on Geographic Names.[1]
Sentinel Mesa is a mesa composed of three principal strata. The bottom layer is Organ Rock Shale, the next stratum is De Chelly Sandstone, and the upper layer is Moenkopi Formation capped by Shinarump Conglomerate. The rock ranges in age from Permian at the bottom to Late Triassic at the top. The buttes and mesas of Monument Valley are the result of the Organ Rock Shale being more easily eroded than the overlaying sandstone.[5]
Spring and fall are the most favorable seasons to visit Sentinel Mesa. According to the Köppen climate classification system, it is located in a semi-arid climate zone with cold winters and hot summers. Summers average 54 days above 90°F annually, and highs rarely exceed 100°F. Summer nights are comfortably cool, and temperatures drop quickly after sunset. Winters are cold, but daytime highs are usually above freezing. Winter temperatures below 0°F are uncommon, though possible. This desert climate receives less than 10abbr=offNaNabbr=off of annual rainfall, and snowfall is generally light during the winter.[6]