A pillar box is a type of free-standing post box. They are found in the United Kingdom and in most former nations of the British Empire, members of the Commonwealth of Nations and British overseas territories, such as Australia, Cyprus, India, Gibraltar, Hong Kong, the Republic of Ireland, Malta, New Zealand and Sri Lanka. Pillar boxes were provided in territories administered by the United Kingdom, such as Mandatory Palestine, and territories with Agency postal services provided by the British Post Office such as Bahrain, Dubai, Kuwait and Morocco. The United Kingdom also exported pillar boxes to countries that ran their own postal services, such as Argentina, Portugal and Uruguay.
Mail is deposited in pillar boxes to be collected by the Royal Mail, An Post or the appropriate postal operator and forwarded to the addressee. The boxes have been in use since 1852, just twelve years after the introduction of the first adhesive postage stamps (Penny Black) and uniform penny post.