Additional fossils briefly mentioned as Eosalmo were reported from Russia, but they have not received close taxonomic treatment since.

Based on preservation of juvenile to adult specimens at some of the sites, the species lived its full lifecycle in freshwater, with no travel from the highlands to the sea as in modern salmon.

Articulated skeletons are known from the type locality Driftwood Shales in Driftwood Canyon Provincial Park, near Smithers, British Columbia, the Allenby Formation surrounding Princeton, British Columbia, Canada and the southernmost highlands sites in the Klondike Mountain Formation surrounding Republic, Ferry County, Washington.

[3] Bone and scale material recovered from coprolites or regurgitalites at the Quilchena site in the Coldwater Beds has been identified as Eosalmo Cf.

Fossils of isolated scales and a preopercle were identified from Quilchena while collecting at the site for study of predation on the fish fauna there.

[2] In 1999 Wilson and Guo-Qing Li published a redescription and phylogenetic assessment of Eosalmo based on an expanded dataset of fossils from Driftwood, Princeton, and Republic.

[3] The position as the oldest Salmonine make it a "key freshwater stem-salmonin" for investigation of Salmon family migratory habits and distributions.

[14] Given its status as the oldest salmonid taxon described and thus the most recent common ancestor, E. driftwoodensis is used as a calibration node or a constraint for phylogenetic analysis of Salmoniform taxa at varying levels.

The scales have a vaguely square outline possessing a nearly centrally located growth origin and with no ridges run from the center to the edges.

[3] Wilson (1977) mentions one fish specimen displaying possible chromatophores scattered on the opercular region but not extending onto the frontal bones.

This range suggests that E. driftwoodensis was completely a freshwater dwelling species rather then being anadromous like may modern Salmon which spend much of their adult life in saltwater.

[1] The fully freshwater lifecycle of Eosalmo is supported by the sister-group placement of the Esocidae (pike and mudminnows) to Salmonidae.

[4] The Eocene Okanagan Highlands sites as a group represent upland lake systems that were surrounded by a warm temperate ecosystem with nearby volcanism.

[18] The highlands likely had a mesic upper microthermal to lower mesothermal climate, in which winter temperatures rarely dropped low enough for snow, and which were seasonably equitable.

The CLAMP results after multiple linear regressions for Republic gave a mean annual temperature of approximately 8.0 °C (46.4 °F), with the LMA giving 9.2 ± 2.0 °C (48.6 ± 3.6 °F).