She was struck by a car on Ford Street at Hughes Circle.
Rondon was transported to Griffin Hospital with serious injuries. At about 9 p.m. police informed Eyewitness News that the girl had died.
The car was being driven by a 54-year-old Gaetan DomPierre, of Ansonia police said. There is no indication of speed or drugs or alcohol. Police are running tests.
The driver did stop when the crash happened and tried to help the girl.
"We heard a big scream, came running out. I saw the car and people gather around," said Peter Kross who lives next door to where the crash happened.
Eyewitness News was told Rondon lived right around the corner and was the baby of the family with two older brothers.
No charges have been filed at this time and the case is still under investigation.
The town’s Boys and Girls Club said in a statement “It is a sad day for all of us at the Boys & Girls Club of the LNV. One of our youngest members of our Smilow unit, 6-year-old Leah Rondon earned her angel wings today. She was a beautiful, energetic young girl that was always smiling. The Rondon family needs our support and prayers at this sorrowful time. Hug the ones you love, and hold dear the moments we all share with each other. You will be missed very much, Leah.”
Ansonia school officials offered condolences to the family of Rondon as well as the family of 6-year-old Nyah Marcano, who was killed in a motor vehicle crash on Route 8 in Shelton this week.
Both girls were from Ansonia.
Ansonia Mayor David Cassetti said he and school officials visited the family on Friday morning.
"Its one of toughest things I've ever had to do in my two years as mayor. This was really tough," Cassetti said.
"Our thoughts and prayers go out to the families, friends and loved ones of these two children," said Dr. Carol Merlone, superintendent of schools.
Rondon would have started school at Mead School and Marcano would have attended Prendergast School.
There will be a benefit ziti dinner at the high school next week and proceeds from Saturday's Rock the Valley Concert at Ansonia's Nolan Field will also be donated.
Grief counselors will be available today and next week at the two schools. Parents are asked to call the school for services: Mead School, 203-736-5090, and Prendergast School, 203-736-5080.
Copyright 2015 WFSB (Meredith Corporation). All rights reserved.
Town mourns death of two girls killed in separate crashesMore>>