Exhibit 99.1

   Gastar Exploration Announces Successful Donelson #3 Bossier Well

    HOUSTON--(BUSINESS WIRE)--June 1, 2007--Gastar Exploration Ltd.
(AMEX:GST) (TSX:YGA) is pleased to announce that it has drilled the
Donelson #3 well, located in Leon County, Texas, to a total depth of
19,200 feet. Based on preliminary analysis of electric logs and
natural gas shows encountered during drilling, the well encountered
approximately 100 net feet of apparent pay in five Bossier sands.
Gastar is in the process of installing production casing to total
depth and will then begin initial completion and testing of the
Bossier pay zones. The initial completion activities are expected to
take approximately 30 days and, if successful, initial natural gas
sales are expected shortly thereafter. Gastar has a 67% after casing
point ("ACP") working interest with Chesapeake Energy Corporation
(NYSE:CHK) owning the remaining 33% ACP working interest.

    Gastar is nearing total depth on the John Parker #3 well and
currently is running intermediate casing. The John Parker #3 well, a
Knowles limestone vertical well, is expected to reach a projected
total depth of 13,850 feet in approximately 10 days.

    J. Russell Porter, Gastar's President and Chief Executive Officer,
made the following comments on these well results, "The Donelson #3
well encountered several Bossier sands that are expected to result in
higher production rates and higher gross ultimate recoverable reserves
than our average Bossier well to date. Further, this well is located
on the crest of the Hilltop structure and is additional confirmation
of the presence of a series of deeper Bossier sands across our Hilltop
structure acreage. We are currently evaluating plans for either a
single zone or multiple zone completion within the Bossier formation."

    Gastar Exploration Ltd. is an exploration and production company
focused on finding and developing natural gas assets in North America
and Australia. The Company pursues a strategy combining select higher
risk, deep natural gas exploration prospects with low-risk coal bed
methane (CBM) development. The Company owns and controls exploration
and development acreage in the deep Bossier gas play of East Texas.
Gastar's CBM activities are conducted within the Powder River Basin of
Wyoming and upon the approximate 3.0 million acres controlled by
Gastar and its joint development partners in Australia's Gunnedah
Basin (PEL 238) located in New South Wales and the Gippsland Basin
located in Victoria.

    Safe Harbor Statement and Disclaimer:

    This press release includes "forward-looking statements" within
the meaning of Section 27A of the Securities Act of 1933 and Section
21E of the Securities Act of 1934. A statement identified by the words
"expects", "projects", "plans", and certain of the other foregoing
statements may be deemed forward-looking statements. Although Gastar
believes that the expectations reflected in such forward-looking
statements are reasonable, these statements involve risks and
uncertainties that may cause actual future activities and results to
be materially different from those suggested or described in this
press release. These include risks inherent in the drilling of natural
gas and oil wells, including risks of fire, explosion, blowouts, pipe
failure, casing collapse, unusual or unexpected formation pressures,
environmental hazards, and other operating and production risks
inherent in the natural gas and oil drilling and production
activities, which may temporarily or permanently reduce production or
cause initial production or test results to not be indicative of
future well performance or delay the timing of sales or completion of
drilling operations, risks with respect to natural gas and oil prices,
a material decline in which could cause the Company to delay or
suspend planned drilling operations or reduce production levels, and
risks relating to the availability of capital to fund drilling
operations that can be adversely affected by adverse drilling results,
production declines and declines in natural gas and oil prices and
other risk factors described in the Company's Annual Report on Form
10-K, as filed on March 27, 2007 with the SEC at www.sec.gov and on
the System for Electronic Document Analysis and Retrieval (SEDAR) at
www.sedar.com.

    The American Stock Exchange and the Toronto Stock Exchange have
not reviewed and do not accept responsibility for the adequacy or
accuracy of this release.

    CONTACT: Gastar Exploration Ltd., Houston
             J. Russell Porter, 713-739-1800
             Fax: 713-739-0458
             rporter@gastar.com
             or
             Michael A. Gerlich, 713-739-1800
             mgerlich@gastar.com
             www.gastar.com