EXHIBIT 99.1

[Crown Castle International Corp. Logo]


MEMO

To:   Directors and Executive Officers of Crown Castle International Corp.
From: E. Blake Hawk and Don Reid
Re:   Blackout Trading Period Relating to 401(k) Plan Provider Change

The Sarbanes-Oxley Act prohibits the directors and executive officers (including
family members) of Crown Castle International Corp. ("Company") from, directly
or indirectly, purchasing, selling or otherwise acquiring or transferring any
common stock or other equity security (including any derivative security
relating to such equity security) of the Company during the Blackout Period (as
described below), if such equity security was "acquired in connection with" the
director's or executive officer's service or employment to or with the Company.
The penalty for violation of the prohibition is a loss of the profits realized
from the transaction.

Information regarding the Blackout Period:

     1)   Reason for the Blackout Period: The Blackout Period will result from
          the Company changing the provider for the Company's 401(k) Plan
          ("Plan") from PNC Bank to Charles Schwab Retirement Plan Services with
          the restriction on Plan participants indicated below.

     2)   Plan transactions to be suspended during, or otherwise affected by,
          the Blackout Period: During the Blackout Period, most Plan
          transactions and information will be unavailable to a Plan participant
          including Plan loan distributions, changes in Plan investment
          elections and trading in Plan funds and assets (including Company
          common stock). Plan contributions and loan repayments can be processed
          during the Blackout Period.

     3)   Description of the class of equity securities subject to the Blackout
          Period: The class of Company equity securities in the Plan subject to
          or affected by the Blackout Period is Company common stock (par value
          $0.01 per share). [Note: The restriction on Company directors and
          executive officers trading during the Blackout Period is applicable to
          all Company common stock and other equity securities "acquired in
          connection with" services or employment to or with the Company as
          indicated above]

     4)   Actual or expected beginning and ending dates: The Blackout Period is
          contemplated to begin on January 24, 2003 and end on or about February
          17, 2003.

If you have any questions regarding the Blackout Period including the
transactions prohibited by Company directors and executive officers during the
Blackout Period, please contact E. Blake Hawk (713-570-3155 or
bhawk@crowncastle.com) or Don Reid (713-570-3147 or dreid@crowncastle.com) at
Crown Castle International Corp., 510 Bering Drive, Suite 500, Houston, Texas
77057.