When Europeans explored Canada, they discovered that all regions were already occupied by native peoples, whom they called "Indians" because:

• They thought they had reached the East Indies.
  Explanation:

  "When Europeans explored Canada, they found that all regions were already occupied by native peoples, whom they called "Indians" due to their mistaken belief that they had reached the Indies."
• They believed the natives came from India.
• They mistook them for South Asians.
• They had been told they were from India.