The Capitol and its grounds were enlarged accordingly, and by 1892 the building had reached essentially its present size and appearance (with the exception of the east front extension 1958–1962 and courtyard infill areas 1991–1993).

Even with the enlargements, Congress eventually grew too big for the building and new facilities had to be constructed to meet the needs of the government.

The most recent large structure within the Capitol complex is the Thurgood Marshall Federal Judiciary Building, which was opened in 1992.

Renovations to the Botanic Garden Conservatory began in September 1997 and continued for four years until December 2001 when the building reopened.

The Conservatory's aluminum framework, glazing, interior floors, doors, and lighting were replaced; all electrical, plumbing, and environmental control systems were upgraded, and air conditioning was added to the display halls.

Despite many delays, the Center opened in December 2008, and includes an exhibition gallery, two theaters, a dining facility, and gift shops.

On January 6, 2021, the Capitol was stormed by supporters of President Donald Trump after a rally in front of the White House.