The name Protohadros means "First Hadrosaur", since it was the first hadrosaur living in the Late Cretaceous. It was slightly smaller than Plateosaurus, being 7-8 metres long and 3 feet tall. Unlike Plateosaurus, it was not a prosauropod. It was found in Texas. It was related to two dinosaurs, which are Altirhinus and Eolambia.