EX-23.1

Exhibit 23.1

CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

We consent to the incorporation by reference in this Registration Statement on Form S-8 of our reports dated February 20, 2018, relating to the consolidated financial statements and financial statement schedule of NiSource Inc. and subsidiaries (the “Company”) (which report on the consolidated financial statements expresses an unqualified opinion and includes an explanatory paragraph relating to the Company’s spin-off of its subsidiary Columbia Pipeline Group, Inc. on July 1, 2015), and the effectiveness of the Company’s internal control over financial reporting, appearing in the Annual Report on Form 10-K of the Company for the year ended December 31, 2017.

/s/ DELOITTE & TOUCHE

Columbus, Ohio

November 1, 2018