The site has been holy ground for fifteen centuries. Crónán of Roscrea founded a monastery here in the sixth century, but the location was 'a wooded morass far from the haunts of men'—so wild that pilgrims got lost trying to reach it. Crónán abandoned it and moved to the more accessible wood of Cré, which became modern Roscrea. In the seventh century the Culdees—Ireland's reformist hermit monks—settled on the nearby Monaincha island. Augustinian canons followed and, in 1485, relocated to Sean Ross. The wood that drove away early Christians eventually became a Georgian estate. Around 1750 the main house, Corville House, was built in cut stone—two storeys over a basement, a walled garden, an icehouse, a lime kiln. The Sisters of the Sacred Hearts of Jesus and Mary arrived in 1932 and the buildings became a convent.

Between 1932 and 1969, Sean Ross Abbey operated as a Mother and Baby Home. Unmarried pregnant women, sent away by their families and a society that treated their pregnancies as moral failure, came here to give birth in secrecy. Their babies were sometimes adopted—often to wealthy Americans, after the 1953 legalisation of adoption in Ireland—and sometimes died. On 27 July 2020, the journalist Alison O'Reilly, who had broken the Tuam Babies story in 2014, published in the Irish Daily Star the names of 1,024 children who had died at Sean Ross. The full death list eventually recorded 1,090 children dying in the home over a thirty-seven-year period. The figure is higher than the 796 children who died at Tuam and the 817 who died at Bessborough in Cork.

The death certificates make difficult reading. 128 children are recorded as dying from 'Marasmus'—severe malnutrition. Others were recorded as dying of convulsions, exhaustion. Two babies died from sun and heat stroke. One child died from acute heart failure as the result of choking on porridge. The historian Catherine Corless, who first uncovered the Tuam names, called the Sean Ross figures 'horrifying' and questioned the cause-of-death entries: 'You wonder were they just putting down anything for causes of deaths, or did the children actually die this way? It seems that when a large group of children died, they said, "we'll put down cardiac arrest for those 15." It's appalling.' The children's names were displayed in 2020 at the 'Stay With Me' art exhibition. They had names. Many of them had been buried, with their mothers' silence, in an unmarked plot the institution called the Angels Plot.

St Anne's Special School opened on the campus in February 1971, providing specialist services to students aged four to eighteen with severe or profound general learning disabilities, or with autism. The Sisters continue to run it. In February 2018, the congregation put much of the campus up for sale—keeping the school and the cemeteries, which they committed to maintain and keep accessible. The Angels Plot is still there. So is the older graveyard beside the ruined Corville Abbey on the grounds. The Georgian house has UPVC windows now and survives as a building of 'special architectural and artistic interest'—a phrase that catalogues the carving but not the children.

Philomena Lee was reunited with her son's story in 2009, half a century after her son had been taken from her, and only after his death. Their case sparked the Mother and Baby Homes Commission of Investigation, which reported in 2021 and led to a state apology from Taoiseach Micheál Martin. There were tens of thousands of women whose names we will never know—mothers separated from their children, working in laundries to repay the cost of their own confinement, forbidden from speaking the names of children adopted out of their arms. Sean Ross Abbey is the building where some of these stories happened. The Angels Plot is the field where some of those children rest. They were not, as the institutions sometimes called them, 'illegitimate.' They were people. They had mothers who loved them. The work of remembering them honestly is recent, painful, and necessary.