MyHeritage is offering six days of free access to its US City Directories collection this week. It will start tomorrow* and run until Tuesday 7 December.
The collection contains records from 25,468 public directories published between 1860 and 1960. City directories were distributed to help residents find local individuals and businesses, and while they come in many different formats, they typically list names (and names of spouses), addresses, occupations, and workplaces.
As such, they constitute a rich source of information for anyone seeking to learn more about their immigrant ancestors in the mid-19th to mid-20th centuries. They can serve as an important alternative to census records where those records are not available — for example, most of the records from the 1890 census, which were destroyed in a fire in 1921. (It wasn't only the Irish who couldn't keep their records safe!)
MyHeritage used algorithmic methods to identify and consolidate records from a total of 561,503,516 entries into one set of records per individual. It has resulted in about 560 million aggregated records, each featuring the same individual who lived at the same set of addresses over the span of multiple years. The records also include images of the original directory pages.
* The free access is officially supposed to start on the 2nd, but appears to be fully open a day early.