granddaughter stole check and forged my name and cashed check, who do i contact to file charges in MD

don't know

You want to prosecute your granddaughter??? You reap what you sow, buddy. File a report with the police or to exopedite things go directly to the District Attorney. In the meantime before you get irrevocably committed to this course of action, reflect on whether you really want to put your own flesh and blood in jail.

You can go to a District Court Commissioner and file an applcation for a statement of charges.