By 1900 police based at the Lock-up included an Inspector, Sub-Inspector, three Sergeants, six First Class Constables, thirteen Constables and one Probationary Constable. The working day was never dull for Newcastle's Police Force, who faced challenges such as controlling the notorious "Bank Corner Mob" in the 1920's and illegal gambling houses in the city. Some iconic events in Newcastle's history were the Coal Strike of 1909, the Clara Street Eviction Riots in the Great Depression and the 1979 Star Hotel Riot.
In 1838 a Court House was constructed by Colonial Architect Mortimer Lewis on the corner of Hunter and Bolton Streets, adjacent to the site now occupied by the Lock-up Museum. It included a Lock-up comprising two cells but by 1855 as the former penal settlement was developing into a flourishing coal export centre, it was deemed inadequate. During this time, population of the city increased dramatically, creating the need for improved policing resources and facilities. The building of the Police Station and Lock-up was completed in 1861. The building now includes six cells - both men's and women's - a very rare example of a padded cell, and two exercise yards separated for men and women.
The series of portraits on show in the museum are striking documents of some of the prisoners who were sentenced as early as 1884. The foyer was once the charge room of the Lock-up with prisoners arrested and brought into this room for charging with one or more convictions. The dock is where prisoners were measured, photographed and charged before being placed in the cells prior to sentence by a magistrate. Once sentenced, they were usually sent to Maitland gaol under police escort in a vehicle known as the 'black mariah'.