A collection of networked devices operating on a diverse set of physical networks presents the problem of how to effectively support communication between devices that share a common location. We propose geographic virtual networks (GVNs) as a means for easily and effectively supporting communication between devices that share a geographic location but may not share the same physical network. Examples for uses of GVNs include a group being able to use collaboration software while in the same room, access to a printer when in proximity to the printer, and being able to hold a chat session with people attending a conference presentation or sitting in a cafe. Our proof-of-concept software provides a multi-platform interface for users to define and join GVNs visually using a map. The server is made up of an application server in PHP, and an application that handles the dynamic creation of VPN servers associated with each GVN. A spatial database stores the geometric identities of the GVNs. The presentation includes a visual flow model of this architecture. Because the application server uses the SOAP web-service, developers can leverage data from this system for use in any application, regardless of a need for an overlay network. Due to the nature of overlay networks, any network application will work on top of this system. Future research on this concept will include switching from client-server architecture to peer-to-peer to allow for improved scalability, and a service directory functionality that would provide social networking and communication within the context of a geographic region.