The external iliac veins are large blood vessels located in the pelvis. They are responsible for draining deoxygenated blood from the lower limbs and pelvic region. These veins run alongside the external iliac arteries, which carry oxygenated blood in the opposite direction. The external iliac veins merge with the internal iliac veins to form the common iliac veins. This connection is crucial for returning blood to the heart. The external iliac veins play an essential role in the circulatory system, ensuring efficient blood flow from the legs and lower body back to the heart.