The fire started in the Hamilton Avenue building just before 6:45 a.m. Thursday.
The two-story building houses stores and office space, although there was one apartment on the second floor for the property manager.
The victim was identified as 60-year-old Judith Musameci.
"The city of New Rochelle and the Police and Fire Departments extend their condolences to the family and friends of Ms. Musameci," officials said in a statement.
Several years ago, developers designed an $18 million plan to add four stories of apartments on top of the art deco base.
"It smelled so bad, and you didn't see no fire, but we could smell smoke and it was heavy like now," said Arthur Beckett, a neighborhood resident. "The next thing I knew, this is what we see."
Four tower ladders continued to fight the fire as the battle stretched into the afternoon. The fire had entered the cockloft and the roof was compromised, according to fire officials
"This is tough to fight because you can't put people in the roof to open it up, once it gets to a certain point it's not practical, so to access the actual flame. You could have the fire here and a whole waterfall right here and it's not going to do anything if you're not hitting the fire," said Chief Andrew Sandor, New Rochelle Fire Department
Surrounding communities joined in the firefighting effort. The building has been in existence since 1929 and is situated next to Town Hall.
The fire was knocked down Thursday evening, but the firefighters remained on the scene to watch out for hotspots.
North Avenue is closed through downtown New Rochelle.
Fire officials say four firefighters were injured. Three of them were taken to the hospital and one was treated and released at the scene.
They say one of the firefighters suffered a cut and three were treated for smoke inhalation.
The cause of the fire is under investigation.
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