SC 14D9/A

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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. 57)

                              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.  57  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,  September 9, 1999,  September 10,
1999,  September 13, 1999, September 14, 1999, September 15, 1999, September 16,
1999,  September 17, 1999, September 20, 1999, September 21, 1999, September 22,
1999,  September 23, 1999, September 24, 1999, September 27, 1999, September 28,
1999,  September 29, 1999, September 30, 1999, October 1, 1999, October 4, 1999,
October 5, 1999, October 6, 1999, October 7, 1999, October 12, 1999, October 13,
1999,  October 14, 1999,  October 18, 1999,  October 25, 1999, October 26, 1999,
October 10, 1999,  November 12, 1999,  November 19, 1999,  December 10, 1999 and
December 21, 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 9.  MATERIAL TO BE FILED AS EXHIBITS.

         Item 9 is hereby supplemented and amended by adding the following:

         Exhibit (a)(43) - Questions and Answers Sheet for Employees of the
                           Company.







                                    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:  December 21, 1999








                                  Exhibit List

         Exhibit (a)(43) - Questions and Answers Sheet for Employees of the
                           Company.

EX-99.(A)(43)

                                                               December 21, 1999


                             FOR COLUMBIA EMPLOYEES


The following is an update on Columbia's progress in its ongoing exploration and
review of strategic alternatives to enhance shareholder value. We hope it
answers questions you may have about the review process and recent reports in
the media.


WHAT IS THE CURRENT STATUS OF YOUR DISCUSSIONS WITH THIRD PARTIES REGARDING A
POSSIBLE TRANSACTION?

Columbia and its financial advisors have received preliminary indications of
interest from numerous companies in connection with our previously announced
process for evaluating strategic alternatives. As a result, we are inviting a
number of these companies, including NiSource, to participate in a second round
of the process.


WHICH COMPANIES ARE BEING INVITED INTO THE SECOND ROUND?

Columbia's Board has authorized management to conduct its discussions with
interested parties in private. This will help prevent rumors and misinformation
from disrupting our business activities. Accordingly, we will not comment on
which companies we are talking to, except that we will make the required
disclosures regarding NiSource due to its unsolicited tender offer.


WHAT KIND OF TRANSACTION DO YOU EXPECT TO PURSUE?

As we announced on Oct. 24, Columbia's Board authorized management to explore
strategic alternatives to generate value in excess of that which Columbia's
business plan or the NiSource proposal could create. We are continuing to
consider a variety of possible transactions, including a merger, reorganization
or the disposition of a material amount of stock or assets. As we have
previously stated, there can be no assurance that any discussions will result in
a transaction or other action.


HAVE ANY OF THE COMPANIES INVITED TO THE SECOND ROUND MADE PROPOSALS THAT WOULD
PROVIDE VALUE GREATER THAN NISOURCE'S UNSOLICITED CASH OFFER OF $74 PER SHARE?

Columbia is inviting into a second round several companies that provided
preliminary indications of interest reflecting a preliminary value higher than
NiSource's unsolicted offer which was raised to $74 per share in cash on Oct.
17.


DOES THIS MEAN THAT COLUMBIA IS DEFINITELY GOING TO MERGE WITH ANOTHER COMPANY?




No. Columbia's Board and management are continuing to explore and evaluate
strategic alternatives that would significantly enhance shareholder value. While
this process might result in a merger, there are other possible scenarios --
including a sale of assets, a sale of stock, or no transaction at all.


WHY IS NISOURCE BEING INVITED INTO THE SECOND ROUND IF COLUMBIA HAS RECEIVED
BETTER PROPOSALS?

Columbia is allowing NiSource to participate in the second round so that it can
have an opportunity to improve its offer, if it so chooses.


WHAT SPECIFICALLY WILL HAPPEN IN THE SECOND ROUND?

All of the companies in the second round -- each of which has executed a
confidentiality agreement -- will have an opportunity to review additional
confidential information about Columbia and then make revised submissions.

WHEN WILL THE SECOND ROUND GET UNDERWAY?

Our objective is to move forward carefully but expeditiously.

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