Most libraries have this book, which visually displays State & counties for
each census year [end in 0]:

William Thorndale and William Dollarhide, Map Guide to the U.S. Federal
Censuses, 1790-1920. Baltimore: Genealogical Publishing Co., Inc, 1987.

Mike RANSOM

> Does anyone know how I could obtain a list of the counties which
> existed in NY in 1824?