POWER OF ATTORNEY


Know all persons by these presents, that the undersigned
hereby constitutes and appoints each of David W. Whitehead and
Edward J. Udovich, signing singly, the undersigned's true and lawful
attorney-in-fact to:

(1)  execute for and on behalf of the undersigned, in the
undersigned's capacity as an officer and/or director of FirstEnergy Corp.
(the "Company"), Forms 3, 4 and 5 in accordance with Section 16(a) of
the Securities Exchange Act of 1934, as amended, (3) ("Section 16") and
Form 144 ("Form 144") pursuant to Rule 144 under the Securities Act of
1933 ("Rule 144") and the rules thereunder;

(2)  do and perform any and all acts for and on behalf of
the undersigned that may be necessary or desirable to complete and
execute any such Form 3, 4, 5 or 144 and timely file such form with the
United States Securities and Exchange Commission and any stock
exchange or similar authority; and

(3)  take any other action of any type whatsoever in
connection with the foregoing which, in the opinion of such
attorney-in-fact, may be of benefit to, in the best interest of, or legally
required by the undersigned; it being understood that the documents
executed by such attorney-in-fact on behalf of the undersigned pursuant
to this Power of Attorney shall be in such form and shall contain such
terms and conditions as such attorney-in-fact may approve in such
attorney-in-fact's discretion.

The undersigned hereby grants to each such
attorney-in-fact full power and authority to do and perform any and
every act and thing whatsoever requisite, necessary, or proper to be done
in the exercise of any of the rights and powers herein granted, as fully to
all intents and purposes as the undersigned might or could do if
personally present, with full power of substitution or revocation, hereby
ratifying and confirming all that such attorney-in-fact, or such
attorney-in-fact's substitute or substitutes, shall lawfully do or cause to be
done by virtue of this power of attorney and the rights and powers herein
granted.

The undersigned acknowledges that the foregoing
attorneys-in-fact, in serving in such capacity at the request of the
undersigned, are not assuming, nor is the Company assuming, any of the
undersigned's responsibilities to comply with Section 16 or Rule 144.

This Power of Attorney shall remain in full force and
effect until the undersigned is no longer required to file Forms 3, 4, 5 and
144 with respect to the undersigned's holdings of and transactions in
securities issued by the Company, unless earlier revoked by the
undersigned in a signed writing delivered to the foregoing
attorneys-in-fact.

		This Power of Attorney shall be governed by and
construed in accordance with the law of the State of Ohio, regardless of
the law that might be applied under principles of conflict of laws.




POWER OF ATTORNEY
	Mark T. Clark
January 27, 2004
Page 2


IN WITNESS WHEREOF, the undersigned has caused
this Power of Attorney to be executed as of this 27th day of January
2004.


/S/ MTClark
___________________________
Mark T. Clark
Senior Vice President
FirstEnergy Service Company


Signed and acknowledged
in the presence of:

/S/Jackie C. Perry
___________________________


/S/Nadine M. Stith
___________________________






State of Ohio		)
		)  ss:
County of Summit 	)


The foregoing Power of Attorney was acknowledged
before me this 27th day of January 2004 by Mark T. Clark.


/S/Susie M. Hoisten
___________________________
Notary Public
Susie M. Hoisten, Notary Public
Residence - Summit County
State Wide Jurisdiction, Ohio
My Commission Expires Dec 9, 2004