Three more names have been added to a memorial honouring Ontario's fallen police officers, including that of a York Region constable killed in the line of duty last year.

Thousands of officers from across the province gathered in Toronto this morning to pay tribute to their fallen colleagues in the 13th annual Ceremony of Remembrance.

Many laid roses at the memorial just east of Queen's Park, particularly at the spot bearing the name of York Regional Police Const. Garrett Styles.

Styles died on June 28, 2011, after he was dragged and crushed by a minivan driven by a 15-year-old boy.

His widow, Melissa, sat near the front for the ceremony, along with the couple's two young children and other family members.

The names of Nipigon Const. George Armstrong and Port Robinson Const. Charles Richards were also added to the monument. They died in 1919 and 1854, respectively.

Armstrong, an Irish immigrant and First World War veteran, was gunned down while investigating a break and enter along the Canadian Pacific rail line.

Richards was shot and killed in the village inn while arresting a man wanted for robbery and murder.

Premier Dalton McGuinty told the solemn crowd words aren't enough to thank officers whose lives are tragically cut short.

"We can only stand here today in memory of these brave officers who made the ultimate sacrifice and pledge to be better, to do good ourselves," he said.

Ontario Lt.-Gov. David C. Onley also attended the ceremony, as did Madeleine Meilleur, the minister of community safety and correctional services.

The names of 251 officers have been inscribed on the Wall of Honour, which was built in 2000.

Eighty-six of them were provincial police officers; 39 served with Toronto police.