The 60th International Mathematical Olympiad will be held in Bath, United Kingdom from 11 to 22 July 2019. Website: https://www.imo2019.uk/
The 59th International Mathematical Olympiad will be held in Cluj-Napoca, Romania from 3 to 14 July 2018. website : http://www.imo2018.org.ro  
The 58th International Mathematical Olympiad was held in Rio de Janeiro, Brazil from 12 to 23 July 2017  website: https://www.imo2017.org.br/
The 57th International Mathematical Olympiad will be held in Hong Kong, from 6 to 16 July 2016.  IMO 2016 will be hosted by the International Mathematical Olympiad Hong Kong Committee Limited with the Hong Kong University of Science and Technology as the Host University and the Education Bureau of the Hong Kong…
The 56th International Mathematical Olympiad will be held in Chiang Mai, Thailand, from 4 to 16 July 2015.  The IMO 2015 will be hosted by The Institute for the Promotion of Teaching Science and Technology (IPST) · Chiang Mai University · The Mathematical Association of Thailand under the Patronage of His Majesty the King · The Promotion of Academic…