The Liberty of St Albans was a liberty situated within Hertfordshire, but enjoying the powers of an independent county. It was originally associated with the abbey of St Albans, and later with the borough corporation. It was absorbed by Hertfordshire in 1874. It was also known as the Hundred of Cashio. The origins of the liberty are unclear, but the abbots of St Albans claimed that the privileges had first been granted by King Offa of Mercia, who founded the abbey in 793. At the time of the Domesday Book the liberty was known as Albanestou. The boundaries of the area expanded over time, including at times parts of Buckinghamshire. It became known by the alternative titles of St Albans Hundred, and eventually as the Hundred of Cashio. Exactly what powers the liberty possessed previous to the twelfth century are not known. Edward I gave the abbot of St Albans palatine powers equal to those enjoyed by the bishops of Durham and Ely. With the dissolution of the abbey the Borough of St Albans was granted a charter of incorporation as a free borough, having previously been under the control of the abbot. The liberty was henceforth placed under the corporation of the borough. Palatine status was discontinued, although the borough and liberty retained its own quarter sessions. The administration was headed by a high steward chosen by the corporation. The liberty was merged with the county of Hertfordshire in 1874 by Act of Parliament, which divided the county into two divisions, the eastern part of the county to be the Hertford division and the western part to be known as the Liberty of St Albans Division, each maintaining separate quarter sessions, but being a single commission of the peace. The Act made clear that, despite its name, the St Albans division was not to be deemed a liberty in any future legislation. In 1889 the Local Government Act 1888 created an elected Hertfordshire county council which covered both divisions. For some time after its creation, the county administration was divided between Hertford and St Albans. By the nineteenth century the liberty contained all or part of the following parishes:
