When you make a journey, your starting point is the place from which you start. They had already walked a couple of miles or more from their starting point
Something that is a starting point for a discussion or process can be used to begin it or act as a basis for it. These proposals represent a realistic starting point for negotiation = basis
beginning point, point of commencement; beginning point, WWW site with links to search engines and useful sites from which users can start to browse the Internet (Computers)