They were found unresponsive on Thursday by two county highway garage employees who were working nearby the pond, which was almost completely frozen over.
Zachery Rogers and Samuel Deatherage pulled Noah to a bank and administrated CPR. Maurissa was pulled out of the water by fire department workers, according to WHIO.
They were both sent to nearby hospitals where they later died of their injuries. It is unclear how long either of them had been in the water.
Shelby County Sheriff John Lenhart said Noah had gotten away from his mother and ran onto the ice.
'She did what all moms and dad do: tried to rescue the child,' he said.
The 10ft-deep pond is on the residential property of the family's next-door-neighbor John Moeller, who returned to his home just moments after the workers discovered Maurissa and Noah.
The neighborhood had agreed that the pond could be used for recreation and fishing and that kids were allowed in the pond as long as they were supervised by an adult, according to Moeller.
But Moeller told WHIO he had never seen Noah by the water before, and that the tragedy had him 'shook up'.
'Realize that life can be very, very brief,' he said.
Moeller said the community was banding together to help Maurissa's husband and daughter.