Pony Express Image Census   A complete census of known transcontinental pony express covers with images

PDF file of the book "The Pony Express, A Postal History" by Frajola, Walske and Kramer (48 meg)

Listing of additions and re-classifications since 2005 publication of book

Pony Express covers for sale
 

Frajola's Board for Philatelists   

A public discussion forum where philatelists from around the world can chat, ask questions, and answer questions. Please join some of the most respected philatelists on the internet. Although United States postal history of the pre 1900 era is frequently discussed, all philatelic topics are welcomed.

Census Site - The PhilaMercury Project

An online image and description database for United States covers that is free and open-access. Over 18,000 covers listed including the Marc Haas collection (info about this aspect here). Database can be browsed or searched, and results may be sorted by date, origin as well as by additional parameters. Instructions and information on how to use this resource are here.

Postal History Resources

Searchable PDF files of United States Post Office Acts and postal rate summaries here. Annotated Additional Page of Links useful for research including newspaper archives, city directories and period source documents. Also, Stanley B. Ashbrook's Special Service links to the cornerstone series, written between 1951 and 1957, relating to the analysis of United States covers.