Municipal bankruptcies are covered under Chapter 9 of the bankruptcy code. Chapter 9 was created in 1934 in the midst of the Great Depression. Chapter 9 has many differences from corporate or personal bankruptcy. First, states can determine if municipalities are permitted to file for Chapter 9. If Chapter 9 filing is allowed the municipality cannot be forced to liquidate assets to cover debts, does not protect collective bargaining agreements, does not protect retiree benefit guarantees, and the bankruptcy judge has no ability to modify bankruptcy plans; he can only approve or reject a submitted bankruptcy plan. (source)
The list below contains a brief account of counties, towns, and cities that either filed for chapter 9 or came close to filing. Note that there are other municipalities that file for chapter 9 that are not a county, town, or city. These special municipalities are setup for special projects: hospitals, sewers, landfills, etc. The list below is only of municipalities that can be found on a map.