The tickets were bought at Redner's Warehouse Market at 2126 N. Fountain Green Road on March 30 and at the 7-Eleven at 1302 Churchville Road on May 1.
The other two unclaimed tickets sold in the state were purchased March 30 at a 7-Eleven in Timonium and May 9 at a Stop & Shop in Lexington Park.
Winners have 182 days from the date of the drawing to claim the tickets.
After taxes, the lucky winners will net $166,000, Maryland Lottery Assistant Director of Communications Erica L. Palmisano said. The stores where the tickets were purchased will receive a $1,000 bonus.
"As far as I know, these stores have not sold top-tier or second-tier Mega Millions or Powerball tickets in the past," Palmisano added.
Other Harford County residents struck it rich playing the lottery late last year.
In September, an unidentified couple from Abingdon won a $108 million Powerball jackpot. They purchased their ticket at Wine World in Abingdon.
In December, 79-year-old Havre de Grace resident Jose Antonetti won a $1 million Powerball play from a ticket he bought at Post Road Liquors in Havre de Grace.