Who is the current Chief Justice of the United States?

The Chief Justice of the United States is the head of the judicial branch of government and plays a crucial role in overseeing the operations of the Supreme Court. John Roberts has held this position since September 29, 2005. He is responsible for presiding over court sessions, leading discussions among justices, and ensuring the Court's proceedings are conducted fairly and efficiently.

The other individuals mentioned have held or currently hold significant positions on the Supreme Court but are not the Chief Justice. Ruth Bader Ginsburg served as an Associate Justice until her passing in September 2020, Clarence Thomas is an Associate Justice who has served since 1991, and Elena Kagan is also an Associate Justice who was appointed in 2010. Their contributions to the Court are substantial, but in the context of this question regarding the current Chief Justice, John Roberts is the appropriate answer.