The park, designed by John Russell Pope years before he began work on the Jefferson Memorial, includes two sites: the Memorial Building, which stands on the farm where Lincoln was born in 1809, and his boyhood home at Knob Creek.
It was at his boyhood home that Lincoln formed his earliest memories, Justice said, such as planting pumpkin seeds between the farm's corn rows.
At Knob Creek, visitors get a more hands-on idea of what those early years were like: The field is "pretty much unchanged," Justice said.
A favorite activity of his at the park is visiting the creek.
"The best thing to my mind, it gives me goose bumps when we go over there, is to stand there," he said, "and look down on the field and contemplate that you're pretty much looking at what Abraham Lincoln saw."