American geographer known for promoting the view that the physical environment determines human history and culture, an idea that provoked much controversy until superseded by later antideterministic approaches.

Semple earned B.A. (1882) and M.A. (1891) degrees from Vassar College in Poughkeepsie, New York, and studied at the University of Leipzig with the German anthropogeographer Friedrich Ratzel (Ratzel, Friedrich). Although not allowed to matriculate at Leipzig, she attended Ratzel's lectures—sitting apart from the male students—and was permanently influenced by his methods and ideas.

Semple's subsequent career alternated periods of writing with periods of teaching at a number of institutions, including the University of Oxford, the University of Chicago, Columbia University, the University of Colorado, Wellesley College, and Clark University. She was professor of anthropogeography at Clark from 1923 until 1932. In 1921 she was elected president of the Association of American Geographers, the first woman to hold that office. Her scholarly works include American History and Its Geographic Conditions (1903), which was adopted as a textbook by several colleges, Influences of Geographic Environment (1911), and The Geography of the Mediterranean Region (1931).