Single-celling is the practice of assigning only one inmate to each cell

Prison cell

A prison cell or holding cell or lock-up is a small room in a prison, or police station where a prisoner is held.Prison cells are usually about 6 by 8 feet in size with steel or brick walls and one solid or barred door that locks from the outside. Many modern prison cells are pre-cast. Solid doors...

 in a prison

Prison

A prison is a place in which people are physically confined and, usually, deprived of a range of personal freedoms. Imprisonment or incarceration is a legal penalty that may be imposed by the state for the commission of a crime...

. John Howard

John Howard (prison reformer)

John Howard was a philanthropist and the first English prison reformer.-Birth and early life:Howard was born in Lower Clapton, London. His father, also John, was a wealthy upholsterer at Smithfield Market in the city...

 has been credited as establishing the practice of single-celling in the United Kingdom

United Kingdom

The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...

 and, by extension, in the United States

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

. In 1957, only 15 prisons in the United States practiced single-celling exclusively while 41 prisons employed it with a portion of their cells and 44 housed multiple prisoners in all of their cells. Critics of single-celling suggest that the practice imposes psychologically harmful isolation on inmates, while advocates argue that single-celling alleviates many of the inmates' discomforts.