What qualifies as western Wisconsin?

For the purposes of this blog, I am focusing on the following counties, roughly to the south of Interstate 90/94 and to the west of Interstate 39 in Wisconsin. I will focus on the trout streams in the following counties:

• Buffalo
• Columbia
• Crawford
• Dane
  
• Dunn
• Eau Claire
• Grant
• Green
  
• Iowa
  
• Jackson
• Juneau
  
• LaCrosse
• Lafayette
  
• Monroe
  
• Pepin
• Pierce
• Richland
• Rock
  
• Sauk
  
• St Croix
• Trempealeu
• Vernon

One could certainly make the case for other counties to be included or some to be excluded, but these are the parameters that made sense to me.