It has been just over a decade since the Supreme Court decided in Kelo v. New London that local governments can take private property by eminent domain under a very broad reading of "public use". Cato held an event earlier this year to examine the legal impact of Kelo, featuring remarks from George Mason Law Professor Ilya Somin based upon his recent book, The Grasping Hand. Not only has Kelo spawned widespread public backlash, but its also given birth to renewed interest by legal scholars. As an economist, I am a little more interested in the direct impact on families.
Unfortunately, I have had no luck finding a database of all U.S. takings. The American Housing Survey (AHS), conducted by the Census Bureau every two years, does, however, offer some estimates. For survey respondents who moved within the previous year, the AHS asks respondents the "main reason" for leaving their previous unit. One option offered is "government displacement". For the survey years since Kelo, the average has been 109,000 households who state that government action displaced them from their previous home. If that average holds for non-survey years, then a good estimate is that just over a million households have been displaced by government action since Kelo.
The AHS also confirms some suspicions as to who the victims of eminent domain are. Since Kelo, about 29% of households displaced by government action have been African-American, about twice that of the general population. As concerning is that about 32% are households in poverty, again about twice the rate of the overall population. If you're poor or African-American, you are twice as likely as households overall to be displaced by government action. Also concerning is that the annual average for families displaced by government action in the decade prior to Kelo is about half that witnessed after Kelo. So despite the public backlash, takings are up not down.
It should be emphasized that the AHS is a sample, not a census. The 90% confidence interval for my million estimate is +/- 107,000. Also keep in mind that government could displace a families by means other than eminent domain. The AHS is also a survey of housing units, so any homeless families would not be included. Lastly responses are based upon household questionnaires and not verified. All that said, a million homes taken since Kelo is likely a good approximation and still troubling.