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Nearctic E. argentella members live in a variety of habitats including arctic tundra, alpine meadows, wetlands and grassland prairie (Kaila 1997). In Alberta, E. orestella adults have been encountered in montane habitats.

Elachista orestella is categorized within the nearctic E. argentella group (Kaila 1997). This group is characterized by having a smooth scaled head, slightly raised neck tufts and antennae that are approximately 2/3 the length of the forewing (Kaila 1997). The wings are lanceolate; the hindwings are grey and translucent and the forewings acute at the tip and typically white (Kaila 1997). Elachista orestella may be mistaken for E. aurocristata but can be separated by the overall size, colouration and genitalic features (Kaila 1997). With a forewing length between 3.1 to 5.7 mm, E. orestella is smaller (Kaila 1997). In E. orestella dark scales create two spots at the midpoint of the forewing and at the 2/3 of the wing at the fold (Kaila 1997). These scales are present but fainter and brownish in E. aurocristata (Kaila 1997). The aedeagus of male E. orestella is shorter than the length of the tegument and uncus combined (Kaila 1997).

In Canada E. orestella can be found in Alberta, Labrador, New Brunswick, Newfoundland Quebec and Yukon (Kaila 1997). In the United States, specimens have been collected in Alaska, Illinois, Massachuesetts, Minnesota, Nebraska, New Jersey, New York and Pennsylvania (Kaila 1997).