Use of a hypertext is growing as multimedia and hypermedia systems become popular. The major difference between hypertext-based and ordinary user interfaces is navigation. Typically, there are two major navigation problems in a hypertext compared to the ordinary user interface: "Disorientation" and "Cognitive Overload". To reduce or eliminate these problems of the hypertext system, a variety of aiding tools have been proposed. Among them, a local map is a good tool for helping users navigate through screens, especially for a large and complex system. This study examined three major design variables of a local map in a hypertext: breadth, depth, and functionality of a map. A human factors experiment was conducted to investigate the effects of these variables. Based upon the results of the experiment, design guidelines are suggested.