Europe, Africa, Asia, America. They went extinct in America when modern humans arrived; or it was climate change (but they did fine when reintroduced and the native population were shown that they were useful beyond being food)
Equus simplicidens lived around 4 million years ago in North America, relying on speed, stamina, and herd behavior for protection from predators like early wolves and big cats. Their survival, much like modern equids, depended on strong social structures and collective awareness. Over time, this lineage spread to other continents via land bridges before becoming extinct in North America. evolved into the distinct species of horses, zebras, and donkeys and where reintroduced into the American continent by humans
Equus simplicidens, also known as the Hagerman horse, lived around 4 million years ago in North America and is considered an ancestor of modern horses, zebras, and donkeys[3][5]. These animals relied on speed, stamina, and herd behavior for protection against predators such as early wolves and big cats[3]. Their survival was supported by strong social structures and collective awareness[3]. Over time, Equus species migrated to other continents via land bridges[4]. They eventually went extinct in North America around 10,000 years ago during the Pleistocene extinction event[1][2][4]. Horses were later reintroduced to the continent by humans in the late 15th century[4].
and they're correct about not using wikipedia as a source, you use wikipedia as a summary and then verify the information in the ACTUAL sources it cites