Trondheim had an environment similar to the Earth nation, Iceland. The planet was mostly tundra and cold seas, but the equatorial region could support human life relatively well. The Summer Islands were a chain islands in the equatorial region where most humans lived. The chief industry appeared to be fishing and hunting Skrika.
The planet had not been settled for very long, with some dwellings in the main city being modified caves.
Skrika were seal-like creatures native to Trondheim that were used in a variety of ways. They could be either eaten or their pelts worn, though Bishop Peregrino noted only "vain women" wore them. In the Summer Islands of the equatorial chain, they came to reproduce in the spring. Skrika was a important part of the Hundred Worlds' luxury trade, with planets such as Cyrillia and Armenia being involved in the buying of them.
Speaker for the Dead
Some time when Trondheim was still a newly-settled world, Andrew Wiggin and his sister Valentine traveled to the planet and lived their for several years. The siblings became teachers, but Valentine started a family with a fisherman named Jakt. After many months, Andrew left the planet to travel to Lusitania. Years later, Valentine, Jakt, and their family left the planet as well.
- Trondheim was named after the Norwegian city, Trondheim.