Bonn Square is named after the German city of Bonn with which Oxford is twinned. It is close to the original west gate of the old city of Oxford.  

For over 700 years, from the 12th century until 1870, the area was the graveyard of St Peter-le-Bailey Church. Although no records exist for the first 400 years of the graveyard's existence, parish records for the period from 1585 to 1870 list around 6,800 burials. The church stood at the front of the square, overlapping on to the present Queen Street. In 1874 the church was rebuilt further up the road (now St Peter's College chapel), and the old church was demolished to make way for a road widening scheme. From 1874 to 2007 the churchyard was a memorial garden, and the Tirah Memorial, the first war memorial erected in Oxford, was appropriately placed there in 1900. The area was named Bonn Square in 1974. The new paved Bonn Square was in 2008.

Bonn Square - Wikipedia