The ileum / lim / is the final section of the small intestine in most higher vertebrates, including mammals, reptiles, and birds. In fish, the divisions of the small intestine are not as clear and the terms posterior intestine or distal intestine may be used instead of ileum.

Where is the ileum located in the body? Okie... think carefully first, then make a decision:
To answer the question, consider the following: The ileum / lim / is the final section of the small intestine in most higher vertebrates, including mammals, reptiles, and birds. So, the answer is the final section of the small intestine.