It happened along the 2600 block of Swarts Street around 9 p.m.
Investigators said 7-year-old Sinsir Parker was shot in the face while getting caught in the barrage of bullets, during a drive-by shooting.
Neighbors said they heard more than a dozen gunshots.
"I heard about 15 shots ring out. I heard it come across the scanner and the Ring that it was a drive-by. I called my local friends on the block and they said two cars came down and just rang out about 15 shots and a little boy caught the bullet in the head," said one resident.
Police have not yet made any arrests.
This is Chester's 14th homicide this year.
Mayor Thaddeus Kirkland announced his intention for the city of Chester to raise a $50,000 reward for information that leads to the arrest.
During a Monday afternoon press conference, Kirkland denounced the violence in the city, while also asking the city's corporate partners for help.
"Unfortunately, we are fighting two fronts in our community," said Mayor Kirkland. "This city, like the rest of the world is dealing with the pandemic of the Coronavirus but we are also facing the epidemic of gun violence."