The Congresswoman from Minnesota was all smiles as she was sworn in on Capitol Hill ... where she was surrounded by a throng of supporters, many of whom were also wearing hijabs. Omar's no stranger to politics -- she served in the state legislature before making her historic run for Congress.

Omar -- the first Somali-American in Congress -- has also never shied away from her religion in public. In fact, during her victory speech on Election night, she dropped the Arabic phrase, "alhamdulillah" ... which means "all praise to God."

The 37-year-old -- who came from a refugee camp in Kenya some 23 years ago -- ran on very progressive platforms ... such as hiking the minimum wage, universal healthcare and free college tuition.