The former New York Mayor Mr Rudolph Giuliani is to take part in a solemn ceremony to mark the anniversary of the World Trade Centre attack.
He will begin a reading at ground-zero of the 2,800 names of the September 11th victims.
The day will include a moment of silence at 8.46 am local time, one year to the minute after American Airlines Flight 11 plunged into the north tower of the World Trade Centre.
Governor George Pataki will then read the Gettysburg Address, the famous speech delivered by President Abraham Lincoln at the dedication of the National Cemetery at Gettysburg.
The ceremony will follow a bagpipe procession to ground zero from points in each of the city's five boroughs, in honour of the hundreds of rescue workers killed.
"Our intent is to have a day of observances that are simple and powerful," Mayor Michael Bloomberg said.
A group of victims' families told city officials they wanted a list of all those who died to be a central part of the commemoration, according to Mr Bill Doyle, who lost his son, Joseph, in the attack.
Several fire stations that lost men in the trade centre are planning private services for families - many of whom said they would avoid the city's ceremony. Some companies that suffered losses also have separate plans.
AP