The hypothalamus is part of the diencephalon, which surrounds the third ventricle of the brain and consists of the thalamus, hypothalamus and epithalamus. The hypothalamus lies inferior to the thalamus and receives inputs from several regions of the brain.
Projecting from its ventral surface is the pituitary gland, or hypophysis. This is a pea-shaped structure that lies in the hypophyseal fossa of the sphenoid bone of the skull and is connected to the hypothalamus by the stalklike infundibulum ('funnel').
Image courtesy of http://commons.wikimedia.org/wiki/File:Hypothalamus_small.gif under the Creative Commons licence.
The next set of images show the location of the hypothalamus from different viewpoints of the brain and in relation to other structures.
Transverse section of the brain. The hypothalamus is adjacent to the third ventricle.
Coronal section of the brain.
Both images courtesy of and adapted from http://www.flickr.com/photos/malcubed/2306269671/ under the Creative Commons licence. Some rights reserved.
This is sagittal section through the brain.
Image courtesy of and adapted from http://www.flickr.com/photos/reighleblanc/3854684694/ under the Creative Commons licence. Some rights reserved.
Bear M.F., Connors B.W., Paradiso M.A. (2007). Neuroscience: Exploring the Brain (3rd Ed). LWW.
Tortora G.J., Nielsen M.T. (2009). Principles of Human Anatomy (11th Ed). Wiley.