The Wassillie Trefon Dena'ina Fish Cache is a historically important fish cache (backcountry food storage structure) that is now listed on the National Register of Historic Places. It qualified for this designation partly because it was a uniquely well-preserved example of traditional Dena'ina Athabascan fish-caching buildings in the vicinity of Lakes Clark and Iliamna. It is about 9 by 10 feet (2.7 m × 3.0 m) in dimension, and is set on poles that are intended to be difficult for animals to climb. It was built without nails or spikes.