Johnston v. District of Columbia was a United States Supreme Court case that dealt with the issue of whether the District of Columbia was liable for damages caused by a defective sidewalk. The plaintiff, Johnston, had been injured when he fell on a sidewalk that had been negligently constructed by the District of Columbia. The Supreme Court held that the District of Columbia was liable for Johnston’s injuries. The Court reasoned that the District of Columbia was responsible for the construction and maintenance of the sidewalks, and thus was liable for any damages caused by a defective sidewalk. The Court also noted that the District of Columbia had a duty to maintain the sidewalks in a safe condition, and that it had failed to do so. The Court’s decision in Johnston v. District of Columbia established that the District of Columbia was liable for damages caused by a defective sidewalk. This decision has been cited in numerous cases since then, and has been used to establish the principle that municipalities are responsible for maintaining public sidewalks in a safe condition.

In Johnston v. District of Columbia, the Supreme Court was asked to decide whether a statute passed by Congress in 1871 that allowed for the appointment of three commissioners to oversee public works projects in Washington D.C., including construction and repairs on roads and bridges, was constitutional. The majority opinion held that it was not unconstitutional because Congress had authority under Article I Section 8 Clause 17 of the Constitution (the Necessary and Proper Clause) to pass such legislation as part of its power over federal territories like D.C.. However, Justice Field dissented from this ruling arguing that while Congress did have some powers over D.C., they were limited only to those necessary for carrying out their enumerated powers listed elsewhere in the Constitution; he argued that since there is no mention anywhere else about constructing or repairing roads or bridges within a territory then this particular act exceeded Congressional authority granted by Article I Section 8 Clause 17 and thus should be declared unconstitutional.