What kind of hats did cowboys wear in the mid-1800’s?

The Wild Bunch

The derby (or bowler) was by far the most popular cowboy hat. Most photographs from that time feature men wearing them, and one of the reasons they were popular is that they stayed on in windy conditions. This photo of the Wild Bunch includes Butch Cassidy and the Sundance Kid. Top hats were also popular. Billy the Kid wore one and his photo can be found using the link. Stetsons did not become popular until the end of that century.