Four experiments examined 3- and 4-year-olds' ability to communicate about containment and proximity relations. One hundred twenty-eight children either described where a miniature mouse was hiding in a dollhouse or they searched for the mouse after the experimenter described where it was hiding. The mouse was always hidden with a small landmark that was either in or next to a large landmark. When describing where the mouse was hiding, children were more likely to successfully disambiguate the small landmark when it was in the large landmark (e.g., under the plant in the dresser) than when it was next to the large landmark (e.g., under the plant next to the dresser). When searching for the mouse, 3-year-olds were faster to initiate their searches when the small landmark was in the large landmark than when it was next to the large landmark. Together, these results suggest that there are informational biases in young children's spatial communication.