Is there data on the circulation numbers for newspapers in the antebellum (pre-1861) United States? I'm also interested in any other pieces of data about these newspapers.
The US Newspapers Directory has a substantial amount of metadata about publication locations & dates, but nothing on circulation. Some bulk data/linked data access is apparently available.
It's part of the broader Chronicling America site, which offers digitised newspapers from 1836 onwards; 1770 titles, 1.36m issues, 9.55m pages. (Of course, the majority of these will be post-1860s)