Exhibit 99.1

    Gastar Exploration Announces Successful John Parker #3 Knowles
                            Limestone Well


    HOUSTON--(BUSINESS WIRE)--June 11, 2007--Gastar Exploration Ltd.
(AMEX:GST) and (TSX:YGA) is pleased to announce that it has drilled
the John Parker #3 well, located in Robertson County, Texas, to a
total depth of 13,900 feet. The John Parker #3 is a vertical well
intended to test and produce the Knowles Limestone formation that was
encountered in the John Parker #2 well. Based on preliminary analysis
of electric logs and natural gas shows encountered during drilling,
the well intersected approximately 34 net feet of apparent pay in the
targeted Knowles Limestone formation. The Knowles Limestone formation
encountered in the John Parker #3 well appears to have very similar
properties to the high porosity and permeability confirmed in the
Knowles in the John Parker #2 well through sidewall core analysis.

    Gastar is in the process of installing production casing to total
depth and plans to complete the well in the Knowles Limestone
formation. The initial completion activities are expected to take
approximately 20 days and, if successful, initial gas sales are
expected shortly thereafter. Gastar has a 50% working interest, with
Chesapeake Energy Corporation (NYSE:CHK) and an unrelated private
exploration and production company each owning a 25% working interest.

    J. Russell Porter, Gastar's President and Chief Executive Officer,
made the following comments on these well results, "Along with the
continued success of our Bossier drilling program, the potential to
demonstrate meaningful synergistic production and reserve potential
from a shallower formation adds to our potential asset and corporate
valuations. Gastar is finalizing plans for a horizontal Knowles
Limestone well to be drilled in the vicinity of the Company's previous
Lone Oak Ranch and John Parker wells. If successful, a horizontal
Knowles well should provide more efficient drainage and potentially
higher production rates than a vertical well."

    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 Information:

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