Started in 1904 this collection includes microbial surveys from commodities, yeasts, filamentous fungi, aerobic spore-forming bacteria, rhizobia, Streptomyces and Actinomycetales.
Collections

American Type Culture Collections
ATCC's microorganism collection includes more than 18,000 strains of bacteria, 2,000 animal viruses and 1,000 plant viruses. ATCC maintains collections of protozoans, yeasts and fungi with over 49,000 yeast and fungi strains and 2,000 strains of protists.

USDA, U.S. Forest Service
Reference collection, with one of the largest collections of Basidiomycetous fungi, with 12,000 isolates representing approximately 1,500 species. New cultures of wood decay fungi are routinely added to the collection.
USDA. Agricultural Research Service
Report describing 12 special collections held by the Agricultural Research Service on animal parasites, fungi, bacteria, insects, nematodes, plants, and seeds.

USDA, Agricultural Research Service, Systematic Mycology and Microbiology Laboratory
The U.S. National Fungus Collections (BPI) are the repository for over one million fungal specimens worldwide and are the largest such collections in the world.
USDA, Agricultural Research Service, Nematology Laboratory
The USDA Nematode Collection database has more than 34,000 records. The database can be searched by genus name, city, state, country.