She added someone had notified police after discovering the bodies in Mile Road shortly after 4pm, on Monday (9pm GMT).
The property is located in Solon Township, northwest of Cedar Springs, reports Xinhua news agency. Sheriff Michelle LaJoye Young told reporters that the area is now a "stable scene", and there is no threat to public safety.
Sheriff LaJoy-Young said in a statement: "I can confirm that we have had a shooting and that there are four deceased individuals on the scene".
"Very sad. Very, very sad", LaJoye-Young said.
The Kent County Sheriff's Department said the kids were elementary school-aged and younger, but refused to provide further information, saying their identities are being confirmed, local media reported.
Investigators said there is likely a second crime scene in connection to the shooting, and it could be where the shootings happened.