More than 60 residential institutions including several top private schools are being investigated by Scotland's national child abuse inquiry.
They are among more than 100 locations where the abuse of children is said to have taken place, chairwoman Lady Smith said.
Six boarding schools or former boarding schools, including Fettes College in Edinburgh and Gordonstoun near Elgin, where the Prince of Wales was once a pupil, are being probed.
Several faith-based organisations, other "major" care providers and local authority institutions are also being looked at by inquiry staff.
Lady Smith, a senior judge who was appointed to the role in July, named a list of places being investigated as she provided an update on the inquiry's progress at a preliminary hearing.
The Scottish Child Abuse Inquiry is examining historical allegations of the abuse of children in care and has been taking statements from witnesses since last spring.
Lady Smith told those gathered at Parliament House in Edinburgh that the inquiry is "determined to get to the bottom of any systemic failures that occurred".
She said 170 people had contacted the inquiry by June last year and "many more have done so since".
Regarding institutions, she said: "So far, we have identified more than 100 locations where abuse of children is said to have taken place but we know that there are many more than that.
"The inquiry team is currently investigating over 60 residential care establishments for children in order to gather, from those who ran them and others, evidence about how children who were being cared for in a range of different settings and by a number of different types of care organisations were treated."
The other schools being investigated are the former Keil School, Loretto School, Merchiston Castle School, and Morrison's Academy when it was a boarding school.
Investigations of institutions run by religious orders the Benedictines, Sisters of Nazareth, Daughters of Charity of St Vincent de Paul, Christian Brothers, Sisters of our Lady of Charity of the Good Shepherd, De la Salle Brothers and Marist Brothers are in progress.
Three Church of Scotland-run establishments being probed are Ballikinrain School, Geilsland Residential School, and the Lord and Lady Polwarth Home for Children in Edinburgh, the hearing was told.
The team is further looking at how children were treated at institutions run by "major care providers" Quarriers, Barnardo's, Aberlour Child Care Trust, while eight homes and secure units across Edinburgh, Glasgow, Perth and Fife are also being probed.
In a 70-minute address, Lady Smith confirmed child migrants will be included in the inquiry.
Staff are said to be working to contact people in countries like Canada, Australia and New Zealand who may have suffered abuse in Scotland, or after being sent abroad as part of past care arrangements.
The chairwoman stressed the inquiry is independent of government, police, prosecutors and other organisations.
The inquiry covers the period within memory of anyone who has suffered abuse, not beyond December 2014.
Public hearings will begin on May 31.
Lady Smith appealed to anyone with evidence to speak to the inquiry and the team is launching a publicity campaign to increase awareness about its work.
"We are determined to find out the truth about what happened to children in care, where, how and why," she said.
"We want to find out why the abuse was not prevented, why it was not stopped, and what needs to be done to protect children in care in the future."
She was appointed to lead the inquiry following the departure of its previous chair, Susan O'Brien QC.
Ms O'Brien is reported to be suing the Scottish Government for £500,000 over claims it forced her out of the role.
A Scottish Government spokeswoman said: "Ministers have acted appropriately at all times to exercise the responsibilities that the Inquiries Act 2005 and other relevant legislation places on them and continue to be committed to the independence of the inquiry."
Established in October 2015, the inquiry is expected to report to ministers within four years, offering recommendations to improve the law, policies and practices in Scotland.