Texas Republican Mayra Flores will become the first Mexican-born woman to serve in Congress.
Flores beat Democrat Dan Sanchez in a special election on Tuesday for the opportunity to represent the Rio Grande Valley.
"I woke up this morning still feeling surreal from everything that's happened over the last 24 hours," she tweeted.
The defeat is seen as a major blow to Democrats, who had carried the South Texas district since it was created in 2012.
Prior to running for Congress, Flores worked as a respiratory therapist.
Flores calls herself a pro-God, pro-life, pro-family Republican and supporter of former President Donald Trump.
The newly-elected Congresswoman reacted to another milestone: earning billionaire Elon Musk's vote. The Tesla Founder said it was the first time he had voted for a Republican.
"Earning Elon Musk’s vote was just the icing on the cake and I can't wait to work with his team," she said.