Final answer:
The girl on the front cover of 'Across a Hundred Mountains' is a representation of a character from the book and not an actual person or known individual.
Step-by-step explanation:
The girl on the front cover of the book Across a Hundred Mountains is not specifically identified. Book covers often use artwork or photographs that are meant to represent the themes or characters in the book without depicting one specific character. In the case of this book, there seems to be no direct attribution to a particular individual as the girl on the cover. The listed references do not directly pertain to the cover's image or provide information about a particular person being depicted. Therefore, the girl on the cover possibly is a representation of a character from the book rather than an actual portrait of a known individual.