This is one of my favorite classroom photos currently in the Archive's collection. Belle C. Scofield did us the wonderful service of writing her name on the chalk board, which gives a great jumping-off point for researching this photo. Maybe one reason I like this photo is because so many that I come across will forever remain anonymous mysteries, and this one has an identifiable person in it; it's like restoring her memory to the world.
Now, one can never be sure, but a search at Findagrave.com turned up only one Belle C. Scofield (click for their entry), born January 16, 1874 in Bristol, Wisconsin (in Kenosha Co.) and died June 5, 1964 in Oshkosh; she is buried in Bristol. If this photo was about the turn of the century, that would put Belle in her late 20s, consistent with the woman we see in the image. Presumably, then, this school would be in either Bristol or Oshkosh.
Further searching found that (from Ancestry.com) Belle's middle name is Calista. She was one of six children born to Chester and Frances Amelia (Young) Scofield. It doesn't appear that Belle ever married or had children of her own, but given this photo, she contributed a lot to the lives of other children, and a whole lot of Wisconsinites are richer for her life.