Semi-circular canals are parts of the inner ear located behind the vestibule
There are three semi-circular canals in each ear which are present at right angles to each other.
They have fluid-filled ducts that are widened at one end called the ampulla.
The ampulla has sensory hair cells which convey the movements of the fluid (which occurs due to the movement of the body) in the semicircular canals to the brain through impulses.
It helps in thereby maintaining the balance of the body.
Hence, the semicircular canals are located in the inner ear.