The Commission of Investigation into Mother and Baby Homes published its fifth interim report on 17 April 2019. It dealt with burial practices.
The report found that more than 900 babies and children died while they were residents of Bessborough.
The commission considered it "highly likely" that some of these were buried on the campus, which at one stage extended over 200 acres.
A search by the commission of official burial places in the Cork area found burial records for just 64 of the children concerned.
The burial places of more than 800 babies and children who died while they were residents of Bessborough are therefore unknown, with the commission concluding that it is likely some of them were buried in unmarked graves.
However, the commission found no physical or documentary evidence of systematic burials in the grounds of Bessborough.
The report says that representatives of the Sisters of the Sacred Hearts of Jesus and Mary told the commission it had very little information on burials as Bessborough's records were held by Tusla, the Child and Family Agency, and it had no access to them.
The report states that a number of the congregation's nuns provided affidavits and/or oral evidence to the commission but "were able to provide remarkably little evidence about burial arrangements".
The commission said this was "difficult to comprehend".
However, the commission did not consider it feasible to excavate the full 60 acres involved, let alone the rest of the 200-acre estate on which there has been extensive building work since the institution closed.
Speaking on the day the fifth interim report was published, Children's Minister Katherine Zappone said: "My message today is that there are a lot of questions that are not answered, I feel deeply for the families who may not get the answers they are seeking. In a lot of cases, the evidence is not there.
"I know some families will be very disappointed that some questions have not been answered, we are disappointed too."
In the report, the commission recalled that members of the public responded "with mostly second-hand information" to the commission's appeal for information on burials in Bessborough and that all of this information was followed up.
"The locations identified as possible burial sites ... were assessed by forensic archaeologists," the report stated.
"Some ... have been built on. To date, no physical or documentary evidence has been produced which suggests that any of the sites identified by members of the public contain human remains," it stated.
Adding together the deaths of so-called "illegitimate" children from Bessborough, St Finbarr's Hospital in Cork and the Cork County Home, the commission established that 1,343 died at the three locations.
"Despite having undertaken intensive investigation, the burial locations of 1,279 of these children remain unknown," the report said.
Read more
Burial plot at Bessborough home examined by commission
Bessborough children buried in unmarked graves as late as 1990
Bessborough Mother and Baby Home operated for much of the last century.
Bessborough House and around 200 acres of farmland, which surrounded it, were taken over by the Sisters of the Sacred Hearts of Jesus and Mary in 1922.
High death rates at Bessborough led to its temporary closure in the 1950s.
The Sisters of the Sacred Hearts of Jesus and Mary continued to operate a mother-and-baby home at Bessborough until the late 1990s.
It is estimated that between 7,000 and 10,000 women gave birth in Bessborough.
The Sisters of the Sacred Hearts of Jesus and Mary also operated mother-and-baby homes at Castlepollard in Co Westmeath and at Roscrea in Co Tipperary.
