"Cascadia is commonly described as a bioregion, or a region sharing common natural and cultural features.  Bioregionalism is a form of localism, or the practice of getting to know one's local better.  By combining the two terms together, Cascadian Bioregionalism becomes a template through which residents of the natural region can re-learn how to live within it in a more localized manner. 

Many factors influence how we describe and define a bioregion.  Shared geography, geology, climate, weather, flora, fauna, watersheds, human culture and history all form layers that, when transposed together, show a logical picture of a place in time.  In a sense our mapping of a bioregion is a letting go, to allow for a full spectrum of influence to define our places - as opposed to the historical human tendency to impose abstract boundaries for the political purpose of exploitation and resource extraction.  When we begin to examine our places with more scrutiny to detail, we begin to understand how it is we must live within them to achieve healthy and lasting communities.

Defining the exact borders of a bioregion is not as easy as drawing a line and creating a border.  The size of a bioregion can vary greatly too, depending on how the term is used.  Cascadia commons uses a loose definition for the region of Cascadia, as the collective group of watersheds that flow through the temperate rainforests of western North America.  This is a definition currently accepted by many “Cascadians” and finds origins in the bioregional movement of 1970's and 80's.  David D. McCloskey, one of the long-time members of this movement, has done extensive writing and mapping in the region for almost 30 years.  His work has led to a better understanding of the metaphorical “rooms of the house” that is Cascadia.  Based on an examination of scale in the bioregion, his definitions of the ecoregions (smaller regions that collectively make up the bioregion - based on similar criteria as the bioregion ) of Cascadia help us to better understand both how to define Cascadia itself, and how we might see the subunits of natural systems within the bioregion.

This idea of scale is important, in that it empowers us through the understanding of how we as individuals are connected to the bioregion, beginning with self and spreading out to community, watershed, ecoregion and bioregion.  Our actions have a myriad of consequences, that when informed by bioregional understanding, can collectively lead us through the necessary reinhabitation of Cascadia."