Firefighters responded to the fire at 11:30 p.m. and had it under control at 1:20 a.m.
Firefighters are investigating to figure out what caused this fire.
They are focusing on a top unit apartment where they believe the fire may have started. It is also the unit where the baby died.
The Vallejo apartment unit where a baby died last night. The fire started at 11:30. pic.twitter.com/grEbojv36X— Amy Hollyfield (@amyhollyfield) February 18, 2016
Several others managed to escape, but many are now without a place to live.
The huge fire that consumed the top floor apartment unit kept a family, neighbors and even firefighters from being able to reach the baby who lived there.
A woman, man and four year old did get out safely, but couldn't get to the infant who neighbors said was 7 months old. "I'm Christian, so I immediately started praying when I heard child was still inside and then when I heard he didn't make it, it was a sad situation," Stephanie Williams said.
Williams lives in the building next door and she heard the mother's screams and then saw the fire. She grabbed her family and ran outside. "I couldn't imagine the pain that she felt standing outside and knowing her child was inside the apartment that was burning," Williams said.
Martha Diaz lives on the other side of the building that burned. She is eight months pregnant and has a 2 year old and 4-year-old child. They all got out safely, but as a mother she could hardly handle the news of what happened next door. "It's sad to see something like that, it's really sad especially when there's a baby inside," Diaz said.
Firefighters said all four units in the apartment building were damaged. The woman inside the apartment with the baby suffered cuts to her hands during her escape and was later treated at a hospital.
Some neighbors said they tried to get to the baby and firefighters tried too. "When the first units arrived on scene, they made an attempt to make rescue, the apartment was not considered tenable, it was too well involved with fire," Vallejo Fire Department spokesperson Kevin Brown said.
Damage to the building was estimated to be at least $140,000.
The name of the infant is not being released at this time.
Officials said at least 13 people have been displaced by the fire and no one else was hurt.