The original residential area in south loop was an area known as "Printer's Row", a small pocket just south of the Loop covering about nine square blocks (Congress Expressway to the north, Michigan Avenue to the east, Roosevelt Street to the south and Financial Plaza to the west). This area was the first to be rehabbed in the area, starting in the early 1980's.
In the past decade , the neighborhood that now represents the South Loop has boomed. Printer's Row is still technically part of the area, as are other sub-neighborhoods like Dearborn Park and River City, but the main borders are now considered to be Congress Expressway to the north, Lake Shore Drive to the east, Cermak Road to the south and the south branch of the Chicago River to the west. Dozens of old warehouses have been converted to condos. Several townhouse complexes have sprung up as well - the largest being the "Museum Park / Museum Campus" area, just east of Michigan Avenue and south of Roosevelt Street. There have been equally as many mid-rise condo buildings built in recent years as well.
A checkered past might be the best way to describe the South Loop's history. In the early 1900's, it was best known as a prostitution district littered with illegal gambling houses as well. Over the years it has changed drastically, and is now considered a great alternative for those wanting to live close to downtown.