The ANSP Algae Image Database contains light micrograph images of diatom taxa from rivers throughout the USA. Many taxa are represented. There are multiple images of several to help represent within-taxon variability. The images were made primarily by ANSP Patrick Center Phycology Section staff as part of their routine analysis of algal samples. Purposes of the database are to: provide a set of reference images for ANSP algal analysts and collaborators to help them maintain consistency in taxonomic identifications help document names of taxa used in papers and reports by providing easy access to representative images make images available to other phycologists as a resource to help with identifications The set of images available here is not meant to be comprehensive or to be taxonomically definitive, but only to show representative specimens that can be used to supplement image resources in the published taxonomic literature. Read the documentation to learn more about the database and how to search for and view images. More images will be added on a regular basis. More information on this dataset can be found in the Freshwater Metadatabase - BFE_71 (http://www.freshwatermetadata.eu/metadb/bf_mdb_view.php?entryID=BFE_71).