Mount Disappointment is a

mountain A mountain is an elevated portion of the Earth's crust, generally with steep sides that show significant exposed bedrock. Although definitions vary, a mountain may differ from a plateau in having a limited Summit (topography), summit area, and ...

in the

San Gabriel Mountains The San Gabriel Mountains ( es, Sierra de San Gabriel) are a mountain range located in northern Los Angeles County, California, Los Angeles County and western San Bernardino County, California, United States. The mountain range is part of the Tr ...

Los Angeles County, California Los Angeles County, officially the County of Los Angeles, and sometimes abbreviated as L.A. County, is the List of the most populous counties in the United States, most populous county in the United States and in the U.S. state of California, ...

with a summit elevation of 5,963+ feet (1,818+ m). It was named "Disappointment" in 1894 when

USGS The United States Geological Survey (USGS), formerly simply known as the Geological Survey, is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, a ...

surveyors in the

Wheeler Survey The Wheeler Survey, carried out in 1872-1879, was one of the "Four Great Surveys" conducted by the US government after the Civil War primarily to document the geology and natural resources of the American West. Supervised by First Lieutenant (lat ...

sighted it from the

Santa Susana Mountains The Santa Susana Mountains are a transverse range of mountains in Southern California, north of the city of Los Angeles, in the United States. The range runs east-west, separating the San Fernando and Simi valleys on its south from the Santa Cla ...

, believing it to be the highest point in the immediate area, decided to use it as their next triangulation point. When they reached the summit, however, they discovered that

San Gabriel Peak San Gabriel Peak is a summit in the San Gabriel Mountains in the U.S. state of California. It was named by the United States Geological Survey in 1894 and is located in the Angeles National Forest. This peak was first named ''The Commodore'' for C ...

half a mile (0.8 km) to the east was higher and it was a disappointment so they moved there instead. A Nike missile site was located there in 1955 and the summit was flattened to accommodate it. The missile site was abandoned in 1965. The mountain top is now an important telecommunications site for both commercial and government organizations.

References

Mountains of Los Angeles County, California San Gabriel Mountains U.S. Army Nike sites Mountains of Southern California {{LosAngelesCountyCA-geo-stub