Streets and pubs were packed with revellers celebrating the second time Shane won the coveted trophy.
It was a case of double celebrations at Dolan's pub as the hostelry celebrated its 70th birthday on Sunday evening also.
Among the big crowd in Dolan's celebrating the bar's 70th anniversary as well as Shane's win in the Irish Open was his uncle Tommy Scanlon (front-centre) who is pictured here leading the cheers.
Celebrations also took place in Esker Hills Golf Club and in Shane's pub and restaurant in Tullamore, the Old Warehouse.
Shane completed a remarkable win in Doonbeg, finishing 11 shots ahead of his nearest contender.
He did so as US President Donald Trump watched on, with the US President having wished the Offaly man best of luck with a handshake earlier that day.
Chants of ‘Ole, Ole’ broke out on the 18th as Lowry hit the green with a ten shot lead.
Incredibly, he finished with another birdie to finish on 23 under, posting 63 for his final round, 11 shots ahead of his nearest contender.
It was a remarkable performance by the Offaly man who grabbed control of the tournament on Friday and never really looked back after that.
An emotional Lowry thanked his wife Wendy and his family for all their support and he looked forward to finally bringing home a trophy to his children.
The trophy was presented by a delighted President Trump.
5. Front L-R: Florrie Cornally, Farrell Cornally and Paddy Weldon with at back; Brian Minnock and Liam Mannion celebrating Dolan's 70th anniversary in the Clara bar on Sunday night.
Front L-R: Florrie Cornally, Farrell Cornally and Paddy Weldon with at back; Brian Minnock and Liam Mannion celebrating Dolan's 70th anniversary in the Clara bar on Sunday night. | Offaly Live Photo: Niall O'Mara
6. Emily Bracken, Kathleen Bracken, Paddy Bracken Jnr and Willy Reynolds enjoying the celebrations in Dolan's Clara on Sunday night
Emily Bracken, Kathleen Bracken, Paddy Bracken Jnr. And Willy Reynolds enjoying the celebrations in Dolan's Clara on Sunday night | Offaly Live Photo: Niall O'Mara
7. Aisling Guilfoyle and Tracey Goode in Dolan's Bar, Clara for the 70th anniversary celebrations.
Aisling Guilfoyle and Tracey Goode in Dolan's Bar, Clara for the 70th anniversary celebrations. | Offaly Live Photo: Niall O'Mara
8. Paddy O'Donovan, Eoin Ivers and William Ivers up from Cork for the celebrations at Dolan's Clara on Sunday night.
Paddy O'Donovan, Eoin Ivers and William Ivers up from Cork for the celebrations at Dolan's Clara on Sunday night. | Offaly Live Photo: Niall O'Mara