Perfect choice of an image! Now I wonder how the place actually did get its name. Dumas Texas too!
Dumas, TX, is named for its founder, Louis Dumas (1856-1923).
Dumas, AR, is named for a planter named William Dumas, who bought the land from a farmer in 1870. It was called “Watson District” until incorporated as “Dumas” in 1904.
Texas and Arkansas were part of the Louisiana Territory at one time. Lots of towns with French names that are no longer pronounced the way their settlers did, I imagine. Nawlins and Battin Roozh being prime examples.