Sheriff Paul Milbrath says the girl was playing in a second-story bedroom of a Town of Ixonia apartment complex Friday about 6:15 p.m.
He says her father was cooking dinner at the time. Meanwhile the girl climbed onto a small ledge that allowed her to look out the screen window and watch her siblings playing in the driveway.
She apparently pushed on the screened window, which gave way. She fell about 20 feet and landed on the concrete driveway.
The toddler was airlifted to Children's Hospital in Milwaukee. Her injuries weren't specified, but Milbrath described them as non-life-threatening.