See How to Verify Mail-in Ballots From Maryland Board of Elections Website
From MD Board of Elections website,
click tab “Voter Registration”,
click “Verification of Registration”,
click “Voter Lookup Website”,
enter your name, DOB, and zip and “Search”,
scroll down to “Status of my mailed-in or provisional ballots”
It will tell you the status including whether it was counted or rejected.
Voter Lookup Website:
