The child was the second baby to be placed in the box at Franciscan Hospital since its installation in 2019.
The baby girl was healthy, officials said. The box is available 24/7 for safe anonymous surrender at 5454 Hohman Avenue in Hammond.
The child was one of three babies who have been surrendered at a Baby Box in Indiana in April.
The boxes were created by Monica Kelsey, who was abandoned as an infant.
"What we are seeing here is proof that safe anonymous surrender is a necessary option for mothers in crisis! We know these mothers love and care for their infants in the most sacrificial way, but are unable to give them what they need. This baby is loved and will be adopted within weeks by their forever family," Kelsey said in a statement.
Safe Haven Baby Boxes are available in Indiana, Ohio, Arkansas, Florida, Kentucky and New Mexico.