Nielsen Hayden genealogy
We are Patrick and Teresa Nielsen Hayden, a married couple of writers and editors in Tucson, Arizona. The database that starts at these two roots shows who we provisionally believe to be our (known) ancestors, plus collateral relatives and associated lines that interest us. This database also includes ancestral lines of several friends and colleagues whose genealogy we've researched, and also some research into the ancestry of several individuals important in the history of science fiction and fantasy. As of August 2022, this site contains information on over 38,000 individuals, including 471 direct ancestors of Patrick and 9,960 direct ancestors of Teresa.
Almost every entry here is based on, and footnoted to, at least one primary or secondary source, public or private, but all of it is subject to revision as new knowledge emerges. (The few exceptions are mostly collateral relatives of Patrick's where what we know comes from in-family knowledge, and we're slowly checking those against independent sources.) It's an absolute certainty that some things presented here will turn out to be wrong. All genealogy is a work in progress.