The Grottoes of North America
http://scgrotto.com
National online headquarters of the Grotto.

The Humanitarian Foundation
http://www.hfgrotto.org
The Humanitarian Foundation is a nonprofit organization to help bring “Special Smiles” to children with special needs by providing much-needed dental care for them. The program helps cover the costs of dental treatment, including hospital and anesthesia costs when needed, for children with Cerebral Palsy, Muscular Dystrophy (and related neuromuscular disorders), Organ Transplant recipients or those with Mental Retardation.

Michigan Grottoes
http://scgrotto.com/Text%20documents/migrotto.html
A list of the Grottoes in the state of Michigan.