Exhibit 21

SUBSIDIARIES OF NISOURCE

as of December 31, 2011

Segment/Subsidiary	State of Incorporation
GAS DISTRIBUTION OPERATIONS
Bay State Gas Company d/b/a Columbia Gas of Massachusetts	Massachusetts
Columbia Gas of Kentucky, Inc.	Kentucky
Columbia Gas of Maryland, Inc.	Delaware
Columbia Gas of Ohio, Inc.	Ohio
Columbia Gas of Pennsylvania, Inc.	Pennsylvania
Columbia Gas of Virginia, Inc.	Virginia
Kokomo Gas and Fuel Company	Indiana
NiSource Retail Services, Inc.	Delaware
ELECTRIC OPERATIONS
Northern Indiana Public Service Company*	Indiana
GAS TRANSMISSION AND STORAGE OPERATIONS
Columbia Gas Transmission, LLC.	Delaware
Columbia Gulf Transmission Company	Delaware
Crossroads Pipeline Company	Indiana
Central Kentucky Transmission Company	Delaware
NiSource Gas Transmission & Storage Company	Delaware

Segment/Subsidiary	State of Incorporation
OTHER OPERATIONS
NiSource Energy Technologies, Inc.	Indiana
NiSource Development Company, Inc.	Indiana
EnergyUSA, Inc.	Indiana
EnergyUSA-TPC Corp.	Indiana
CORPORATE
Columbia Energy Group	Delaware
NiSource Finance Corp.	Indiana
NiSource Capital Markets, Inc.	Indiana
NiSource Corporate Services Company	Delaware
NiSource Insurance Corporation, Inc.	Utah
NIPSCO Accounts Receivable Corporation	Indiana
Columbia Gas of Ohio Receivables Corporation	Delaware
Columbia Gas of Pennsylvania Receivables Corporation	Delaware

* Reported under Gas Distribution Operations and Electric Operations.

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