Indiana Code Title 32. Property § 32-19-1-2

Sec. 2. (a) For the purpose of the use of the systems described in section 1 of this chapter, Indiana is divided into an east zone and a west zone.

(b) The area included in the following counties constitutes the east zone:

Adams

Allen

Bartholomew

Blackford

Brown

Cass

Clark

Dearborn

Decatur

DeKalb

Delaware

Elkhart

Fayette

Floyd

Franklin

Fulton

Grant

Hamilton

Hancock

Harrison

Henry

Howard

Huntington

Jackson

Jay

Jefferson

Jennings

Johnson

Kosciusko

LaGrange

Madison

Marion

Marshall

Miami

Noble

Ohio

Randolph

Ripley

Rush

St. Joseph

Scott

Shelby

Steuben

Switzerland

Tipton

Union

Wabash

Washington

Wayne

Wells

Whitley.

(c) The area included in the following counties constitutes the west zone:

Benton

Boone

Carroll

Clay

Clinton

Crawford

Daviess

Dubois

Fountain

Gibson

Greene

Hendricks

Jasper

Knox

Lake

LaPorte

Lawrence

Martin

Monroe

Montgomery

Morgan

Newton

Orange

Owen

Parke

Perry

Pike

Porter

Posey

Pulaski

Putnam

Spencer

Starke

Sullivan

Tippecanoe

Vanderburgh

Vermillion

Vigo

Warren

Warrick

White.