- The Circle of Willis is a critical vascular structure located at the base of the brain.
- It is a ring-like arterial formation that provides collateral blood flow between the major cerebral arteries, ensuring adequate blood supply even if one part becomes occluded.
- This anatomical feature is situated in the region where the internal carotid arteries and the vertebral arteries converge, specifically around the optic chiasm and the pituitary gland.

- Understanding the location of the Circle of Willis is essential because it plays a vital role in maintaining cerebral perfusion and helps protect the brain from ischemic events by allowing redundant circulation.

Reference: Gray's Anatomy, 42nd Edition, Head and Neck Section, Chapter on Cerebral Circulation / Page 1150