The pale enargia or aspen twoleaf tier is a moth of the family Noctuidae. It has a boreal-transcontinental distribution, occurring across the Canadian boreal plain and then southward through the western cordillera at higher elevations, where it is presumably limited by the availability of trembling aspen and possibly other poplars. Records range from northernmost British Columbia and south-western Northwest Territories east to New Brunswick. It has also been reported from Nova Scotia, Ohio and New York. In the western United States it is known from western Montana, Idaho, Washington, Oregon, Nevada, Utah, Wyoming, western Colorado, New Mexico, and Arizona. There are no records from the Rocky Mountain front ranges of Colorado, where it would be expected to be widespread if there is a continuous distribution southward into New Mexico and Arizona. The populations from west of the Rocky Mountains south to New Mexico and Arizona may represent a distinct species.