Two experiments extended earlier research showing age-and intelligence-invariance in memory for spatial location. Second and sixth graders, college students, and mildly retarded persons relocated pictures after looking through a 100-picture book. There were no differences due to age, IQ, or instruction (intentional or incidental) in location memory; there were differences in picture recall. In a second experiment persons with Down syndrome, as a group, were less accurate in location memory than were college students, but many individuals performed as accurately. A 3-month follow-up on the subjects with Down syndrome revealed greater consistency in location memory than in recall. Overall, the results show that young children and mildly mentally retarded persons process spatial location information as well as do college students. Some, but not all, of the more severely mentally retarded persons had deficits in processing memory for location. All persons with mental retardation had deficits in effortful processing as reflected by free recall.