If I am only applying to the University of Maryland President's Postdoctoral Fellowship program, do I need to provide information about a University of California mentor?

No. The on-line application may be used to apply to one or both programs. Those applicants who are only applying to the University of Maryland President's Postdoctoral Fellowship program must identify a faculty mentor at the University of Maryland, but do not need to identify a faculty mentor at the University of California.