Final answer:
The Pacific Coast Mountains, including the Chugach Mountains and the Coast Mountains, run in the southeast of Alaska.
Step-by-step explanation:
The mountains that run in the southeast of Alaska are part of the Pacific Coast Mountains, specifically the coastal range within this system. This range includes the Chugach Mountains, which contain the Chugach Metamorphic Complex, known for its sequence of metamorphic rocks like phyllite and gneiss. The Coast Mountains in Southeast Alaska are also part of this system, extending through British Columbia, down the western United States to northern Baja California, and include other prominent ranges such as the Saint Elias Mountains and the Fairweather Range.