There has been a jail on this site since 1811 when one was established in the basement of the court building and was “primarily” used to hold runaway slaves, beggars and the insane. At this time, Elizabethtown was part of Essex County and it was Newark, the County seat where criminals were housed.

When Union County was formed in 1858, plans were developed for a new Court House at the jail in Elizabethtown, the new county seat. This building was opened in 1862 and used until a new addition was made to the Court House in 1927.

Records in 1902 indicate that the average daily population was fifty inmates. This included juveniles, some of whom were under ten years of age.

A new jail was opened in 1927 adjacent to that facility and included detention rooms for inmates with tuberculosis or other medical problems, a solarium, kitchen, laundry, consultation rooms and two tiers which could double bunk thirty four inmates in each. A reception area and visiting booths were included on the ground floor of this jail. This facility had room to hold about 75 inmates. In 1931, an additional 17 tiers were added to the jail which increased the holding capacity by 180 cells to a total of slightly more than 250 inmates. This jail was in use until April 2001.

The newest addition and current location to the jail complex was opened in 1989 and had a planned capacity of 550 inmates. As of this day, the inmate population has increased over 3000% since 1902. Today, the current Union County Jail houses approximately 1048 inmates. 933 are in housed in the jail in Elizabeth, 122 in Delaney and Logan Halls in Newark which is part of the Union County Drug Court program. Of the total population, 933 males and 115 females.

Noteworthy is that, between 1865 and 1898, four executions by hanging were conducted here, most taking place in the yard between the courthouse and the jail. All offenders were convicted of murder.

In NJ, the practice of hanging continued till 1907 when the electric chair was designated the official means of carrying out court ordered capital punishment.