Rygall's swamp is an oddly placed mire, in the middle of a clear plain. It is actually the result of the drains of Aertael flowing through an underground channel until the flow collects, seeping through to the surface and creating a large permanent swamp. It has attracted monsters over the years, but not often and not many.
The swamp was named after the royal engineer who developed the plan to route all of the city's sewers into the underground and away from the city.