The Infantry of the British Army, part of the structure of the British Army, comprises 47 infantry battalions, from 19 regiments. Of these, 33 battalions are part of the Regular army and the remaining 14 a part of the Army Reserve. The British Army's Infantry forms a highly flexible organisation, taking on a variety of roles, including armoured, mechanised, air assault and light.
Traditionally, regiments that form the combat arms of the British Army (cavalry and infantry) recruit from specific areas of the country. Infantry regiments had been assigned specific areas from which they would recruit from by the mid eighteenth century. These were formalised under the Cardwell Reforms that began in the 1860s. Under this scheme, single battalion infantry regiments were amalgamated into two battalion regiments, then assigned to a depot and associated recruiting area (which would usually correspond to all or part of a county). The recruiting area (usually) would then become part of the regiment's title. It was this that gave rise to the concept of the "county regiment", with the local infantry regiment becoming part of the fabric of its local area.
Over time, regiments have been amalgamated further, which has led to recruiting areas of individual regiments increasing in size. Often, these amalgamations have been between regiments whose recruiting areas border each other. However, there have been occasions where regiments of a similar type, but from widely different areas, have been amalgamated. Two modern examples have been the Royal Regiment of Fusiliers (amalgamated from the county regiments of Northumberland, Warwickshire, City of London and Lancashire, all of which were regiments of fusiliers) and The Light Infantry (amalgamated from the county regiments of Cornwall, Somerset, Shropshire, South Yorkshire and Durham, all of which were regiments of light infantry).