Nathrop is a ghost town and a U.S. Post Office located in Chaffee County, Colorado, United States. The Nathrop Post Office has the ZIP Code 81236.
Nathrop was named for Charles Nachtrieb, owner of the townsite.
Nathrop is located at 38°42′39″N 106°08′33″W / 38.71083°N 106.1425°W (38.710697,-106.142521).
Ruby Mountain is a rhyolite outcrop located about one mile northeast of Nathrop. Small spessartite garnet crystals are found throughout the outcropping. Small pebbles of black obsidian referred to as "Apache tears" by collectors can also be found in the talus rock at the base of the cliffs.