EXHIBIT F-1


                                                   May 24, 2004

Securities and Exchange Commission
450 Fifth Street, N.W.
Washington, DC  20549

         Re:  FirstEnergy Corp. - File No. 70-10205
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Ladies and Gentlemen:

         We have examined the Application or Declaration on Form U-1, as amended
(the "Application"), under the Public Utility Holding Company Act of 1935, as
amended (the "Act"), filed in the above-referenced proceeding by FirstEnergy
Corp. ("FirstEnergy"), and the orders of the Commission dated March 26, 2004 and
May 5, 2004 authorizing the transactions proposed therein.

         The Application requests authorization for certain proposed amendments
to FirstEnergy's Amended Articles of Incorporation and Amended Code of
Regulations (together, the "Governing Documents") and for the solicitation by
FirstEnergy of proxies from its shareholders for use at its 2004 annual meeting
(the "Solicitation") in connection with such proposals as well as in connection
with the adoption of certain director and executive compensation plans (the
"Plans").

         We have examined copies, signed, certified or otherwise proven to our
satisfaction, of the Governing Documents of FirstEnergy. We have also examined
such other documents, instruments and agreements, including the Plans, and have
made such further investigation as we have deemed necessary as a basis for this
opinion. We understand that, at the annual meeting of FirstEnergy's shareholders
held on May 18, 2004, proposals to declassify FirstEnergy's board of directors
and to adopt the Plans were approved but that proposals to amend the Governing
Documents to reduce certain supermajority voting requirements were not approved
by the requisite shareholder vote and, therefore, will not be implemented.

         We are members of the bars of the States of New Jersey and New York and
are not expert in the laws of any jurisdiction other than the laws of such
states and the federal laws of the United States of America. As to all matters
herein which are governed by the laws of the State of Ohio and the Commonwealth
of Pennsylvania, we have relied upon the opinion of Gary D. Benz, Esq., which is




being filed as Exhibit F-2 to the certificate under Rule 24 filed in this
proceeding.

         Based upon and subject to the foregoing, we are of the opinion that:

          (a)   all State laws applicable to the proposed transactions have been
          complied with;

          (b)   FirstEnergy is validly organized and existing in the State of
          Ohio; and

          (c)   the proposed transactions (to the extent that they have been
          implemented) did not violate the legal rights of the holders of any
          securities issued by FirstEnergy.

         We hereby consent to the filing of this opinion as an exhibit to the
certificate under Rule 24 filed in this proceeding. This opinion may not be
relied upon by any other person for any other purpose.

                                           Very truly yours,


                                           Thelen Reid & Priest LLP



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