The Ancient Order of Druids was founded in England in 1781 as a secret society, rather similar to the Freemasons.

By the early twentieth century it had become a more open, general society with aims "convivial, fraternal and philanthropic". The group was the first to practise rituals at Stonehenge in the historic period and adopted the site for ordination of its members on 25th August 1905 when around 700 modern druids gathered at the monument to take oaths and welcome new acolytes. Later, the group shared the site with another organisation, the Church of the Universal Bond.

In 1935 the group held its 150th congress at Stonehenge and can still be reached today, listed under Druids in the London telephone directory.

Source

Chippendale, C, "Stonehenge Complete", Thames and Hudson, London, 2004, pp172-3