Whitehorse's paintings draw upon a personal iconography, based on her reflections of her natural surroundings. She brings together Navajo cosmological perspectives with abstraction in her work. Whitehorse's work is deliberately apolitical. She has described her work as having a sense of chaos and randomness, and said that when she paints she is continually moving the paper around "so I have no idea which way is top and which way is bottom when I paint." Whitehorse credits her grandmother, a weaver, as the most influential artistic figure in her life. More generally, she also draws on Navajo methods of making dry paintings and weavings in her work. Her paintings are usually oil on paper, mounted on canvas, such as "Movement", in the collection of the Honolulu Museum of Art. This work, from 1989, demonstrates the luxuriant, atmospheric, and meditative abstractions for which she is known. Her work is represented in public collections throughout North America, Europe, Japan, Uzbekistan and Morocco.