The author's ability to create convincingly alive characters is as evident [in Forbidden Frontier] as in her other books, but Mrs. Harris has such a lot to say about the times, the people, and the problems that she has crammed too much into one story. Events move fast enough to hold readers, however, and girls who read the book for the story of Alison and Megan will learn a great deal about the settlement of the Far West. (pp. 182-83)

Ruth Hill Viguers, in The Horn Book Magazine (copyright © 1968 by The Horn Book, Inc., Boston), April, 1968.