The 27-year-old mum died following an incident at a property in Donaghadee.
The First Minister and Deputy First Minister led tributes to Ms Montgomery after she was found unconscious at a property in the Elmfield Walk area of Donaghadee.
Paramedics arrived at the scene to administer medical care but the PSNI confirmed she was pronounced dead at the scene.
A post on social media from Donaghadee Lifeboat paid tribute to the young mum: ‘It was with deep shock and great sadness that we learned of the death of Sarah Montgomery over the weekend.
‘Sarah was a highly regarded member of our fundraising branch here at Donaghadee RNLI, regularly attending and helping out at fundraising and station events to support the lifesaving work of the charity.
‘Sarah was the granddaughter of former crew member Arthur Arbuckle. Sarah's late mother Linda was also an active member of our fundraising branch.
‘We extend our deepest sympathies to Sarah’s children, siblings, grandparents, and wider family and friends. Our thoughts are with you at this difficult time. #OneCrew’
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Sarah Montgomery, who was 27, was the mother of two young girls and pregnant with her third child when she died at her home in Donaghadee, County Down.One of the tributes left outside the house at Elmfield Walk Photo: presseye
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Sarah Montgomery, who was 27, was the mother of two young girls and pregnant with her third child when she died at her home in Donaghadee, County Down.One of the tributes left outside the house at Elmfield Walk Photo: presseye
3.
Sarah Montgomery, who was 27, was the mother of two young girls and pregnant with her third child when she died at her home in Donaghadee, County Down.One of the tributes left outside the house at Elmfield Walk Photo: presseye
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Sarah Montgomery, who was 27, was the mother of two young girls and pregnant with her third child when she died at her home in Donaghadee, County Down.One of the tributes left outside the house at Elmfield Walk Photo: PRESSEYE