Suburbanization
St. Louis hit its population peak in the 1950s. The GI housing act, the construction of highways and roads, the increased ownership of the automobile, and inner city blight all led to suburbanization. Because of the city and county split of 1874, St. Louis lost huge numbers to outside municipalities and experienced a decline of about 60% of their population over the next 50 years. As St. Louis lost residents, they also lost tax revenue - causing further blight and disinvestment in the city's core.