There are so many properties in the U.S. that it is difficult to track all. Though, government agencies do this as part of their job. Nonetheless, a lot of those can possibly match the number of tax delinquent homeowners.
Each U.S. state has counties that do their task of going after unpaid property taxes. The Internal Revenue Service or IRS as well as other taxing entities can file a tax lien on your property. They would do this if you do not pay your property tax, income tax, and others. Furthermore, like any other countries, the U.S. can impose the lien on tax delinquent homeowners.