Examination of detailed geographical information on U.S. housing transactions from 1993 to 2009 find much heterogeneity at the neighborhood level in when the recent boom began, how big the initial jumps in price growth were, how long the booms lasted, and what types of neighborhoods boomed first. There is less neighborhood-level heterogeneity in when the bust began and in aggregate price appreciation during the boom. This heterogeneity suggests that there was no one dominant cause of the boom. We also comment on how very local data may help understand the role of contagion, among other housing market phenomena.