The choroid plexus is present in multiple locations within the brain, specifically within the ventricles. The brain has four ventricles: two lateral ventricles, a third ventricle, and a fourth ventricle. Each of these ventricles contains a choroid plexus.
The lateral ventricles are the largest and most prominent ventricles in the brain. There is a choroid plexus located within each lateral ventricle. The choroid plexus of the lateral ventricles extends into the frontal, parietal, temporal, and occipital lobes of the brain.
The third ventricle is a narrow, centrally located ventricle between the right and left halves of the brain. The choroid plexus is found within the walls of the third ventricle.
The fourth ventricle is a small, diamond-shaped cavity located at the back of the brainstem, just above the spinal cord. The choroid plexus is present within the fourth ventricle as well.
So, in total, there are choroid plexuses in each of the four ventricles of the brain: two in the lateral ventricles, one in the third ventricle, and one in the fourth ventricle.