Maryland
Generally, a person must be 18 to get a tattoo in Maryland. However, if the client is under the age of 18, a tattoo is still possible if the parent or guardian provides signed consent. The tattoo parlor is required to keep the consent document on file for at least three years along with the client’s name, artist name, date, and description of the procedure.
http://en.wikipedia.org/wiki/Legal_status_of_tattooing_in_the_United_States