The guide primarily aims to cover the moths (Geometridae only so far) of eastern North America. We are most experienced with the moths of the mid Atlantic states and the Northeast, but are including all moths in the US and Canada with known distributions extending at least partially east of 100 W longitude.

Mostly just for interest, we are also treating the moths of some North Atlantic or arctic islands, including Greenland, Iceland, Saint Pierre & Miquelon, the Svalbard Archipelago, Jan Mayen, the Faroe Islands, Bermuda, and the Azores. We feel that this provides a lot of perspective at very little cost as there are relatively few extra species on any of these islands.