Software engineers often need to locate where particular features of a program are implemented in order to fix a bug or introduce an enhancement. This paper describes a tool called TraceGraph to support this task, particularly for large, long-running or interactive software. TraceGraph provides a simple visual display of the program's trace which allows changes in execution to be easily distinguished. A software engineer can run the feature he or she is interested in, and immediately view how program execution varies. Case studies on two large systems show how TraceGraph may be applied to different kinds of traces. Displays similar to TraceGraph would be good candidates for inclusion in software monitoring or debugging systems.