The blaze broke out shortly after noon in a sixth-floor apartment on Undercliff Avenue in Highbridge. A 39-year-old woman and two children, a boy and a girl, both 3, were able to get out.
Inside the apartment, firefighters found the baby and another 39-year-old woman, whom neighbors identified as his foster mom. Officials believe she tried to rescue the child and they were both overcome by smoke.
The two women and the older kids were in stable condition, suffering smoke inhalation. The baby was pronounced dead at Lincoln Hospital. Their names were withheld pending notification of their families.
Neighbors were stunned by news of the tragedy.
"Every morning I saw him," said Nilsa Estrada, who lives in the apartment next door. "He's a very happy, playful baby. Wherever she [the foster mom] went, he was right behind her. She always held him by the hand."