President of the United States during the 21st century:

1. George W. Bush (2001–2009) – Bush, a Republican, was the 43rd President. He won the controversial 2000 presidential electio1n against Al Gore and served two terms. His presidency was marked by the September 11 terrorist attacks and subsequent wars in Afghanistan and Iraq.

2. Barack Obama (2009–2017) – Obama, a Democrat, was the 44th President and the first African American to hold the office. He served two terms and focused on healthcare reform, economic recovery, and ending the wars in Iraq and Afghanistan.

3. Donald Trump (2017–2021) – Trump, a Republican, was the 45th President. He won the 2016 presidential election against Hillary Clinton but lost the 2020 election to Joe Biden. His presidency was marked by controversial policies, contentious political rhetoric, and two impeachments.

4. Joe Biden (2021–present) – Biden, a Democrat, is the 46th President. He served as Vice President under Barack Obama from 2009 to 2017. Biden won the 2020 presidential election against incumbent Donald Trump and assumed office on January 20, 2021. His presidency has focused on addressing the COVID-19 pandemic, economic recovery, and various domestic and foreign policy issues.

These are the presidents who have served during the 21st century up to the date of my last update.