Fault-block mountains are located in regions where the Earth's crust is being pulled apart, or extended. This extension causes the crust to break along faults, and the blocks of rock on either side of the fault move vertically, creating a series of uplifted and lowered blocks.

Here are some prominent locations where you can find fault-block mountains:

* The Basin and Range Province in the Western United States: This region spans from Nevada to Arizona and is characterized by a series of alternating mountain ranges and valleys, created by fault-block activity.

* The East African Rift Valley: This vast geological feature is a zone of intense tectonic activity where the African plate is being pulled apart, creating a series of fault-block mountains and volcanoes along its flanks.

* The Rhine Graben in Europe: This valley system is a classic example of a fault-block depression surrounded by uplifted blocks, forming a series of mountains along its edges.

* The Sierra Nevada in California: Though primarily formed by volcanic activity, the Sierra Nevada also exhibits features of fault-block mountains, particularly in its eastern slopes.

It's important to remember that not all mountains are fault-block mountains. Other types of mountains exist, such as volcanic mountains, fold mountains, and dome mountains.