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                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549


                                 SCHEDULE 14D-9

                SOLICITATION/RECOMMENDATION STATEMENT PURSUANT TO
             SECTION 14(d)(4) OF THE SECURITIES EXCHANGE ACT OF 1934
                               (AMENDMENT NO. 26)

                              COLUMBIA ENERGY GROUP
                            (NAME OF SUBJECT COMPANY)


                              COLUMBIA ENERGY GROUP
                      (NAME OF PERSON(S) FILING STATEMENT)

                          COMMON STOCK, PAR VALUE $0.01
                         (TITLE OF CLASS OF SECURITIES)

                                    197648108
                      (CUSIP NUMBER OF CLASS OF SECURITIES)

                              MICHAEL W. O'DONNELL
                SENIOR VICE PRESIDENT AND CHIEF FINANCIAL OFFICER
                              COLUMBIA ENERGY GROUP
                            13880 DULLES CORNER LANE
                             HERNDON, VIRGINIA 20171
                                 (703) 561-6000
   (NAME, ADDRESS AND TELEPHONE NUMBER OF PERSON AUTHORIZED TO RECEIVE NOTICE
        AND COMMUNICATIONS ON BEHALF OF THE PERSON(S) FILING STATEMENT)

                                    COPY TO:

                             NEIL T. ANDERSON, ESQ.
                               SULLIVAN & CROMWELL
                                125 BROAD STREET
                            NEW YORK, NEW YORK 10004
                                 (212) 558-4000

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         This  Amendment  No.  26  amends  and  supplements  the   Solicitation/
Recommendation  Statement  on  Schedule  14D-9  filed  with the  Securities  and
Exchange  Commission on July 6, 1999, and as subsequently  amended July 6, 1999,
July 9, 1999,  July 12, 1999,  July 15, 1999, July 16, 1999, July 20, 1999, July
22, 1999, July 30, 1999,  August 3, 1999, August 4, 1999, August 5, 1999, August
6, 1999,  August 9, 1999,  August 11, 1999,  August 12,  1999,  August 13, 1999,
August 16, 1999, August 17, 1999, August 19, 1999, August 31, 1999, September 2,
1999, September 3, 1999, September 7, 1999 and September 9, 1999 (as so amended,
the "Schedule  14D-9"),  by Columbia Energy Group, a Delaware  corporation  (the
"Company"),   relating  to  the  tender  offer  by  NiSource  Inc.,  an  Indiana
corporation,  to purchase  for cash  through its  wholly-owned  subsidiary,  CEG
Acquisition Corp., a Delaware corporation, all of the outstanding common shares,
par value $0.01 per share, of the Company (the "Offer").  Capitalized terms used
but not defined herein have the meaning ascribed to them in the Schedule 14D-9.

ITEM 6.  RECENT TRANSACTIONS AND INTENT WITH RESPECT TO SECURITIES.

         Item 6 is hereby supplemented and amended by adding the following:

         On September 9, 1999, pursuant to its previously  announced  repurchase
program,  the Company  purchased 100,000 Shares on the open market at a weighted
average price per share of $58.3869.





                                    SIGNATURE

         After reasonable  inquiry and to the best of my knowledge and belief, I
certify that the information  set forth in this statement is true,  complete and
correct.



                                            COLUMBIA ENERGY GROUP




                                            By:   /s/ Michael W. O'Donnell
                                               ---------------------------------
                                            Name:  Michael W. O'Donnell
                                            Title:  Senior Vice President and
                                                    Chief Financial Officer


Dated: September 10, 1999