They defeated St Cillian's on Sunday by seven points.
Birr secured back-to-back Offaly Senior Camogie Championship titles at the weekend.
They claimed a 1-15 to 0-11 win over St Cillian's in St Brendan's Park in Birr to make it two-in-a-row.
Sarah Harding got the only goal of the game, with Mairead Jennings ending the game with 0-09 and Sheila Sullivan producing a Player of the Match performance.
Birr will now represent Offaly in the Leinster Championship.
Meanwhile, St Rynagh's struck two late goals to see off Kilcormac-Killoughey in the Senior B decider.
The game ended 2-10 to 2-05.