The former Alaska governor will be addressing a class of 27 seniors at the school in northeastern Washington.
The Spokesman-Review reports the seniors launched an aggressive social media campaign last fall to land Palin as speaker.
The key event may have been a class picture taken in April with a banner that said: "We Want You! Governor Palin!" The photo was posted on Facebook.
On April 18, school officials learned that Palin would be coming to graduation at the high school gym, which holds about 700 people and is expected to be packed.
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