"East along the great highway of the River Isis"

River Thames
Creative Commons Attribution Share AlikeRiver Thames - Credit: Tom Pennington

The Isis is the name by which the section of the River Thames that runs through Oxford is known.

In Victorian times, it was held that Isis was the correct name for the river as far downstream as Dorchester, where it meets the River Thame and becomes the "Thame-isis" (abbreviated to Thames).

Ordnance survey maps still label the Thames as the "Thames or Isis" down to Dorchester, but this has lost common usage outside of Oxford.