"There's no better place to kick off the Tea Party Express than Harry Reid's hometown," Palin said at the rally, dubbed "Showdown in Searchlight," aimed at conjuring up support for the Senate Majority Leader's defeat in November elections.
Activists - some of whom are calling the gathering the largest retirement party in the world - hope it will carry a strong symbolic message.
Reid, the Senate majority leader, is credited with helping push through Congress the controversial health care bill that President Barack Obama signed Tuesday, as well as the so-called "fixes" measure that passed Thursday.
"Washington has broken faith with the people that they are to be serving," Palin told the crowd, which numbered in the thousands.
Palin said the message to government leaders was "loud and clear."
"The big government, the big debt, Obama-Pelosi-Reid spending spree is over. You're fired," she said, prompting cheers from the crowd.
Palin's speech Saturday echoed many of her recent appearances at Tea Party events as she promoted "common sense conservative values" and decried "elites in Washington" and big government spending.
She addressed recent criticism of a post on her Facebook page that called for conservatives not to retreat in the wake of the health care vote, but "reload." Some critics have suggested the post encouraged violent acts against those who voted in favor of the legislation.
"Let's clear the air right now," she said. "We're not inciting violence. Don't get sucked into the lame-stream media lies about Americans standing up for freedom. it's a bunch of bunk that the media is trying to feed you. Don't let them try to divert" attention from the issue.