Hirundum is a large farm in Temeria, about 15 miles west of the Gors Velen. It has many orchards, gardens and fish ponds and provides food for all the surrounding cities. Geralt wound up there on a contract to find a monster which was said to have been killing people.
"Hirundum's not a city," he said. "It's a huge farm. There are orchards and gardens there which supply vegetables and fruit to all the towns and cities in the area. There are also fishponds where they breed carp and other fish."
— pg(s). 68, Time of Contempt (UK edition)