One-room jail

In some areas of the United States, a small, free-standing, one or two room jail building is known as a calaboose, meaning "dungeon" in Spanish.

Calaboose were mainly used to incarcerate prisoners for minor crimes, such as drunkenness in public or fighting, or as a temporary holding cell for when a prisoner awaited transportation to a county jail.

Texas, with its large number of counties, has the highest concentration of historic calaboose jail buildings with over 100 known structures.

Many calaboose have only a single cell, feature a curved or vaulted ceiling, and were constructed of solid concrete, although brick, stone and wooden examples also survive.

Basically a large metal cage with either one or two cells, strap-iron jails were commonly used in the United States in the mid to late 19th century.