This paper will explore notions of limit, boundary, and edge to gain a better understanding of what constitutes a place-world. Not only its contents -- things, people, buildings -- but their corners and surfaces are essential to the layout of places in a given world, human or natural. Architectural discourse concerning "space," "place," and "region" has become increasingly prominent in the last decade, yet without a coherent vocabulary of the precise ways in which places and regions are bounded or open (e.g., in the case of the outskirts of a city), their full sense is not attained. Employing phenomenological description and Gibsonian ecological concepts, Casey will pursue what it means to be situated in the world around us through its several kinds of edges.