Dennis Witmer was born and raised on a farm in Lancaster, Pennsylvania. He moved to Kotzebue, Alaska in 1987, and to Fairbanks in 1991. His photographs of Alaska come both from the remote roadless areas of Northwest Alaska, and from the more developed and populated areas along the Alaska road system. He attempts to record the typical elements of the landscape, incorporating natural elements along with the additions made to the landscape by the consumer culture.

Over the past decade, Witmer's work has been included in over 60 exhibits, including twenty one-person shows, and numerous invited and juried shows. His work is included in the collection of the University of Alaska Museum, the Anchorage Museum of History and Art, the Alaska State Museum in Juneau, and in many private collections.