The Federal Reserve Bank of New York has a fascinating and user-friendly way of presenting their data on mortgage financing, delinquencies, foreclosures and so forth across the nation for different types of mortgages. They have put together a point-and-click map of the US so you can see where the mortgage credit problems are hitting the hardest, with detail as fine as the county. Note that the places where the foreclosures and defaults are the largest are those places with high increases in house prices. The other main contributing factor is of course the economy and job losses. The Associated Press has a complementary figure that plots some mortgage outcomes data with unemployment data. Again, there is a large correlation between high unemployment in a county and high delinquency and foreclosure rates.