The room is entirely private but easily accessible to both the Senate chambers and the press gallery. The unusually large space features a fireplace, arched ceilings, and a sweeping view of the National Mall, described by The Hill as being like an 'upscale clubroom'. The third floor 'Kennedy Hideaway' – so-called as it was long occupied by Senator Edward Kennedy – is considered the most luxurious hideaway to occupy and, according to The Hill, is the 'pinnacle of insider prestige'. The offices assigned to the most senior senators are often lush and expansive. Hideaways are assigned by the Senate Rules Committee based on seniority. By the end of the 20th century there were about 75 hideaways, but in 2010, the number of hideaways was increased to 100 to accommodate all senators who wish to have one, after basement space opened up from the relocation of a Capitol police office into the newly opened Capitol Visitor Center. Writing about Barbara Mikulski's hideaway, Politico described it as being in 'an unmarked room accessed by corridors and staircases reminiscent of the ones that appear and disappear at Hogwarts'. Many hideaways are situated in what the Associated Press has described as 'ancient nooks' of the centuries-old Capitol. Hideaway offices are located on all four floors of the Capitol building, including the basement level. The opening of the Russell Senate Office Building in 1909, and the United States Supreme Court Building in 1935, resulted in the vacancy of additional space in the Capitol, where senators quickly started squatting. When the Capitol opened in 1800, senators were assigned no workspace other than their desks on the floor of the Senate chamber and so appropriated unused spaces throughout the complex. Senate hideaways date to the earliest occupancy of the U.S. In addition to these primary offices, Senators are allocated a single-room office in the United States Capitol, informally known as a hideaway. Members of the United States Senate and their staff have office suites in either the Dirksen Senate Office Building, the Russell Senate Office Building, or the Hart Senate Office Building in Washington, D.C.

However, they proliferated in the early 20th century.

The history of hideaways dates to the earliest occupancy of the U.S. Hideaways are assigned to senators based on seniority. They range from lavish and expansive upper-floor offices to small, cramped offices in the basement. Senators use hideaways as a private space to prepare for sessions of the Senate, conduct confidential meetings, take naps, and for other personal purposes. Their locations are unlisted in any official directory, and their doors are marked only by a room number.

Capitol building used by members of the Senate and by a few senior members of the U.S. The United States Senate's hideaways are about 100 secret offices in the U.S. Secret offices used by members of the United States Senate Hideaways are secret offices located in 'ancient nooks' of the United States Capitol building

The office building inside