Johnson City is a city in Clackamas County, Oregon, United States. The population was 566 at the 2010 census. Because of its small area, its population density is over 8,000 per square mile, making it the most densely populated city in Oregon.[5]
On June 16, 1970, the residents of a trailer court owned by Delbert Johnson voted 49-to-10 to incorporate. Johnson had started the development in 1959, and in 1968 was unsuccessful in having the area annexed to Gladstone. The 55th Oregon Legislative Assembly in 1969 established a boundary review board to prevent an increase in small incorporated cities, but proponents of Johnson City's incorporation had filed for an election before the law took effect.[6]