Richardson and Neeson married in 1994
A medical examiner in New York has said the actress Natasha Richardson died following an accidental blunt impact to the head while skiing.
Prayers have been said in County Antrim for the family of Richardson, the wife of Ballymena-born Liam Neeson.
Richardson, 45, suffered head injuries after a fall at a ski resort in Quebec on Monday. She died on Wednesday.
Many of Neeson's relatives, including his mother, Kitty, still live in the Ballymena area.
Prayers have been said during Mass at All Saints Church.
Politicians in the area have expressed their sympathy to Neeson, who was at his wife's bedside when she died.
North Antrim MP Ian Paisley, DUP, said it was a "terrible, unplanned and tragic loss."
"To Liam and his two boys I express my sadness and prayers for them for the loss of their wife and mother," he said.
"And to Liam's mother in Ballymena who has lost her daughter-in-law I too extend my prayerful sympathy at this time."
North Antrim MLA Declan O'Loan of the SDLP said: "There is immense pride here in the achievements of Liam Neeson as an internationally known actor and one of great distinction.
"His large family circle in Ballymena and the surrounding area are very well known and highly respected. We are all thinking of them at this time of sadness."
North Antrim MLA Robert Coulter of the UUP said: "Our thoughts and prayers are with Liam and his two sons at this time of loss.
"We are very proud of Liam and of the way he never forgets his home and we feel keenly for him and his loss."
The first and deputy first ministers have also offered their "sincere condolences" to Neeson and his family.
Martin McGuinness attended an event in New York on Sunday along with Natasha's mother, actress Vanessa Redgrave.
"It is such a tragedy for two young boys to lose their mother so suddenly. We are all thinking of them and praying for them at this deeply distressing time," he said.
Liam Neeson is the patron of the Lyric Theatre in Belfast.
Its artistic director, Richard Croxford, said the death was a tragedy.
"Everyone at the Lyric is deeply shocked and saddened by this terrible tragedy," he said.
"Our thoughts and prayers are with Liam and his family at this difficult time."
Local tributes have been paid to Natasha Richardson
Part of the Redgrave acting dynasty, Richardson was the daughter of Vanessa and director Tony Richardson, and the sister of Nip/Tuck star Joely Richardson.
Neeson and Richardson married in 1994 and had two sons Michael, 13, and Daniel, 12.
The accident happened while the actress was taking a supervised skiing lesson at a Quebec resort.
Richardson initially showed no sign of injury but about an hour later she was taken to a nearby hospital after feeling unwell. It was later confirmed her injuries were critical.
Neeson, 56, flew from the set of his new film in Toronto to be with his wife as soon as he heard news of the accident.
Alan Nierob, Neeson's publicist, said: "Liam Neeson, his sons, and the entire family are shocked and devastated by the tragic death of their beloved Natasha.
"They are profoundly grateful for the support, love and prayers of everyone, and ask for privacy during this very difficult time."