esphs.us/ Empire State Postal History Society

www.stampinsider.org/ Federation of NY Philatelic Societies

uspcs.org/ US Philatelic Classics Sosiety 
 
rfrajola.com/ Frajola Philatelic's site

usstamps.org/ The U.S. Stamp Society

linns.com/ Linn's Stamp News

machinecancel.org/ The International Machine Cancel Society

postal-markings.org/ The Auxilary Markings Club

askphil.org/b25.htm Stamp Collecting Starts here

postalmuseum.si.edu National Philatelic Museum

sil.si.edu/silpublications/postal-history/local-mail-posts/ Local Mail Posts in the U.S.

americantopicalassn.org/ American Topical Association