O’Hara, who plays club cricket for Wolverhampton, blasted an unbeaten 306 in his side’s draw with Northamptonshire at Holcot.
The 17-year-old opener’s score was a new county record, while his second wicket partnership with Dan Grounds was the highest-ever recorded in a Staffordshire under-17 match.
O’Hara’s innings, which lasted 449 balls, included 37 fours and a six and helped Staffordshire to amass a total of 570-7 declared.
Delighted coach Jamie Turner said: “It was a brilliant innings to watch.
“Archie is a quality player who is a naturally aggressive player. In this instance, he showed a great deal of patience and he didn’t give up a chance from the first ball to the last. His partnership with Dan was crucial.
“For such a young player he showed a huge amount of maturity. It was very impressive.”