The light-colored mountainous regions on the Moon are called highlands.

Here's why:

* Composition: They are composed primarily of anorthosite, a light-colored, feldspar-rich rock.

* Age: They are the oldest surface features on the Moon, formed during its early history.

* Elevation: They are generally higher than the darker, smoother maria (Latin for "seas").

So, while the "seas" are actually vast impact basins filled with dark, volcanic basalt, the highlands are the ancient, uplifted, and often cratered crust of the Moon.