Mobile Post Office Society

Catch and Deliver Apparatus, Auction 233 lot 199

Mobile Post Office Society (MPOS) was founded in 1950 by a group of philatelists interested in the study of United States Highway Post Offices. It soon expanded to focus on Railway Post Offices, and eventually to the enroute distribution and postmarking of mail all over the world. It is a nonprofit organization, affiliate #64 of the American Philatelic Society.

MPOS has published the definitive studies of postmarks from the Railroad, Station, Route Agent, and Messenger services, and the Railway, Highway, Streetcar, Terminal, and Air Mail Field Post Offices as well as the Transfer Offices and Clerks in United States philately. Most recently, MPOS has added a focus on the USA's Rural Free Delivery (RFD) service and postmarks that were used around the beginning of the 20th century. 1996 saw the start of a study of "TRANSIT" markings used at intermediate Post Offices.

The research and work of many years culminated in the completion of the "United States RPO Postmark Catalogue", begun by the late Charles Towle, and completed through the efforts of MPOS Past President Fred MacDonald, along with the work of many dedicated philatelists.

MPOS publications are available for purchase by interested philatelists, whether or not they are members of MPOS. Current members receive all benefits of membership including a subscription to Transit Postmark Collector and MPOS serial publications; Sustaining and Patron members enjoy the serial publications and extra publications at no charge, plus price reductions for all literature. Sustaining and Patron members also get the satisfaction of knowing that they support an organization of dedicated, like-minded philatelists and its scholarly research, as well as its fun activities and show participation.

Annual dues for membership in MPOS are $20/year for "ordinary" membership which includes a subscription to "Transit Postmark Collector," the award-winning quarterly journal of MPOS. "Sustaining" membership is available for $35/year, which includes an additional publication per year at no extra charge. "Patron" membership is $50/year which includes two publications and an extra discount on literature. "Family" membership is available for an additional $5/year. A dues discount of $3 is offered annually to early payers. There is a $3 initiation fee for first-time members. Part of the dues for "Sustaining" and "Patron" membership can be considered to be a tax-deductible contribution to MPOS, and all outright contributions to MPOS are tax-deductible.

 MPOS Auction #233 closes Tuesday, August 2, 2022. There are covers for most every interest and price range.

 Membership and Catalog combo promotion

 SELECTIONS, Volume 11 is now available for $10 from the Society containing 60 pages of interest to collectors and historians. The index and preface can be seen at this link

 MPOS is on Facebook!

  MPOS Show and Meeting Calendar.

 MPOS Books and Literature Pricelist

Note: Prices have been reduced on some literature and several publications are now available in digital format! Please send literature requests to Mobile Post Office Society, PO Box 1058, Poulsbo, WA 98370-0048. You can email our literature rep here. MPOS Members get a discount from list prices as shown at the end of the pricelist. AS OF FEBRUARY, 2018 literature payments via paypal are accepted!

MPOS is moving into the 21st century with release of the publications below in computerized format. They are presented on CD-ROM, as text-searchable PDF files. Dropbox is available for those who don't have a CD-ROM drive. Any are available on a USB Thumb drive for an additional $5.00.

·        THE US RPO CATALOG  (1400+ pages) is $30.00 postpaid. The catalog is text-searchable and updates are included. Here are two sample pages.

·        THE US ROUTE AND STATION AGENT CATALOG, including addenda, is $30.00 postpaid.


·        US STREETCAR MONOGRAPHS, long out of print, are now available as a complete set (14 cities plus a new section on the Chattanooga Electric Car.) The price is $30.00 postpaid. An updated 2019 CROSSREFERENCE:News from the Cities is available hardcopy or electronic

·        The Narrow-Gauge Mail Routes and Cancellations book is priced at $10.00, including updates. Click for an excerpt.

·        John Kay's Directories of RPO lines and Route Agent lines priced at $25.00 for both volumes.


  MPOS RPO Covers for sale to members only

  MPOS HPO Covers for sale to members only

 CD-ROM of films of RPO activity available through MPOS.

 MPOS Press Releases

 Overseas members: Dues payment and electronic subscription at same price as US Domestic membership! See membership/catalog promotion:
Please make payments to Mobile Post Office Society (

 US Postal Bulletins Online 1880-1971 A comprehensive, searchable database of all the daily and weekly Postal Bulletins. MPOS is one of the primary sponsors of this project. A superb source of information for Postal historians.

 TPO and Seapost Society Sister Organization (UK) for collectors of worldwide Travelling Post Offices and Seaposts - a superb site for all types of philatelic research

Click for a Printable MPOS membership application. You may also write to MPOS, PO Box 427, Marstons Mills MA 02648.

Care to comment to the keeper of this page?

Rick Kunz' RPO Postmark home page

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