The term 'Country Containing Ancient Mesopotamia' can be answered with the four-letter word 'Iraq'. Iraq is a country located in the Middle East, bordered by Syria, Turkey, Iran, Kuwait, and Saudi Arabia. It is home to the ancient Mesopotamian civilization, which was one of the earliest civilizations in the world. Iraq has a long and complex history, and has been ruled by various empires over the centuries. Today, Iraq is a republic with a parliamentary system of government.