One of the best books I ever purchased is "Map Guide to the U.S. Federal Censuses 1790-1920" by William Thorndate & William Dollarhide. I am sure you can find it on the web some where, try google.com and put the name in the search box. This book is a map guide showing outline maps at ten-year intervals, the old county boundaries being superimposed over the modern lines. So at a quick glance you can see what counties the one you are working on was formed from. The maps start with 1790 and end with 1920. In the preface it says once the 1930 census is released they will be adding 1930 to any new editions. There may be sites on the Internet now that has the same maps but this book covers every state in the US and they are all in one book not on several different sites on the web. I do not remember what I paid for this book nor where I purchased it, I have had it for about 10 years. I can't tell you how many times I have referred to this book and it has been a great help in keeping me on track as to which county to look for records. The only thing it is lacking is the exact date of the formation for each counties. For PA that can be found at on the following website. http://www.pagenweb.org/formation.html

And it's available at various sources but very expensive! You'd do a lot better searching out websites. [email protected] wrote: >One of the best books I ever purchased is "Map Guide to the U.S. Federal >Censuses 1790-1920" by William Thorndate & William Dollarhide. I am sure you can >find it on the web some where, try google.com and put the name in the search >box. > >This book is a map guide showing outline maps at ten-year intervals, the old >county boundaries being superimposed over the modern lines. So at a quick >glance you can see what counties the one you are working on was formed from. The >maps start with 1790 and end with 1920. In the preface it says once the 1930 >census is released they will be adding 1930 to any new editions. There may >be sites on the Internet now that has the same maps but this book covers every >state in the US and they are all in one book not on several different sites on >the web. > >I do not remember what I paid for this book nor where I purchased it, I have >had it for about 10 years. I can't tell you how many times I have referred to >this book and it has been a great help in keeping me on track as to which >county to look for records. The only thing it is lacking is the exact date of >the formation for each counties. For PA that can be found at on the following >website. > > http://www.pagenweb.org/formation.html > > >==== PACUMBER Mailing List ==== > Search this mail list. > Just type in pacumber or PACUMBER. > http://searches2.rootsweb.com/cgi-bin/listsearch.pl > >============================== >Search the US Census Collection. Over 140 million records added in the >last 12 months. Largest online collection in the world. Learn more: http://www.ancestry.com/s13965/rd.ashx > > > > >