In order to investigate elementary school students' understanding of historical time, this study conducted open-ended interviews with 58 children in kindergarten through sixth grade. The students were asked to place nine illustrations from various periods of American history in chronological order and to talk about the reasoning behind the order they chose. The paintings and photographs consisted of scenes broadly representative of a particular era, such as the colonial period, the 1920s, or the 1960s. The study found that even the youngest children made some basic distinctions in historical time and that those distinctions became increasingly differentiated with age. Dates, however, had little meaning for children before third grade; and although third- and fourth-graders understood the numerical basis of dates, only by fifth grade did students extensively connect particular dates with specific background knowledge. At all ages, children's placement of most pictures revealed substantial agreement with each other and with the correct order. Two appendixes contain copies of the illustrations used in the study and the interview protocol. (MDM)