Exhibit 99.1

                                                                      NEWS
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KeySpan Corporation                                        For Immediate Release

Contacts:         Investors                                Media Relations
                  George Laskaris                          Andrea Staub
                  718.403.2526                             516.545.5052
                                                           516.824.1241 (pager)




               KeySpan Completes Exchange With Houston Exploration
                         Exchange Valued at $449 Million
                        Reduces Ownership Interest to 24%


New York, June 2, 2004 - KeySpan today announced the successful completion of an
exchange  transaction with The Houston Exploration Company (NYSE: THX) valued at
$449 million,  which reduced  KeySpan's  ownership of Houston  Exploration  from
approximately 55% to 24%.

Under the terms of the  transaction,  KeySpan  exchanged  10.8 million shares of
Houston  Exploration common stock for all the stock of Seneca-Upshur  Petroleum,
Inc., a wholly owned  subsidiary  of Houston  Exploration.  Houston  Exploration
retired 4.6 million shares and issued 6.2 million shares in a public offering.

Based on the Houston  Exploration  announced offering price of $48.00 per share,
KeySpan's  Seneca-Upshur's shares were valued at the equivalent of $449 million,
or $41.57 per share.  Seneca-Upshur's  assets consist of  Appalachian  producing
properties  valued  at  $60.0  million  dollars,  and  $389.0  million  in cash.
Seneca-Upshur's  proven  reserves  of 50.5  billion  cubic feet of  natural  gas
equivalent  (Bcfe) represent  approximately 7% of Houston  Exploration's  proved
reserves.


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A member of the Standard & Poor's 500 Index,  KeySpan Corporation  (NYSE:KSE) is
the fifth  largest  distributor  of  natural  gas in the  United  States and the
largest  in the  Northeast,  operating  regulated  gas  utilities  in New  York,
Massachusetts  and  New  Hampshire,   serving  2.5  million   customers.   These
customer-focused businesses are complemented by a portfolio of service companies
which  offer  energy-related  products,  services  and  solutions  to homes  and
businesses. KeySpan is also the largest electric generator in New York State. We
own approximately 6,600 megawatts of generating capacity, providing power to 1.1
million  customers  of the  Long  Island  Power  Authority  on Long  Island  and
supplying  approximately  25  percent  of New York  City's  capacity  needs.  In
addition to these  assets,  KeySpan  has  strategic  investments  in natural gas
exploration, production, pipeline transportation,  distribution and storage, and
Canadian gas processing.  KeySpan has headquarters in Brooklyn,  New England and
Long   Island.   For   more   information,   visit   KeySpan's   web   site   at
www.keyspanenergy.com.





Certain  statements  contained  herein  are  forward-looking  statements,  which
reflect  numerous  assumptions  and  estimates and involve a number of risks and
uncertainties.  For these statements, we claim the protection of the safe harbor
for  forward-looking  statements  provided by the Private Securities  Litigation
Reform Act of 1995. There are possible  developments that could cause our actual
results  to  differ   materially   from  those   forecast   or  implied  in  the
forward-looking  statements.  You are cautioned  not to place undue  reliance on
these forward-looking statements,  which are current only as of the date of this
filing.  We  disclaim  any  intention  or  obligation  to update  or revise  any
forward-looking  statements,  whether  as a result  of new  information,  future
events or otherwise. Among the factors that could cause actual results to differ
materially are: general economic conditions,  especially in the Northeast United
States;  available  sources and costs of fuel;  volatility of energy prices in a
deregulated  market environment as well as in the source of natural gas and fuel
used to generate electricity;  potential write-down of our investment in natural
gas properties  when natural gas prices are depressed or if we have  significant
downward  revisions  in our  estimated  proved gas  reserves;  federal and state
regulatory  initiatives that increase competition,  threaten cost and investment
recovery and impact rate structure;  our ability to successfully reduce our cost
structures;  implementation of new accounting standards;  the degree to which we
develop unregulated  business ventures,  as well as federal and state regulatory
policies  affecting our ability to retain and operate those  business  ventures;
our  ability to identify  and make  complementary  acquisitions,  as well as the
successful  integration of those acquisitions;  inflationary trends and interest
rates; and risks detailed from time to time in reports and other documents filed
by us with the Securities and Exchange Commission.


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