American Stamp Catalogues

Overview US Stamp Catalogues

US Stamp Catalogues (books)

US Stamp Auctions/Marketplaces

Catawiki

Ebay

US Online Stamp Catalogues

Michel (German/English) – Most complete online stamp catalogue with actual prices (subscription required)

Colnect (all language) – Colnect (premium) has auto-matching, best matches and an extensive free stamp catalogs

USA Postage Stamps (English) – Complete free US stamp catalogue with Stanley Gibbons and Scott numbering

Vista (English/French) – Complete free catalogue of the USA with Scott numbering

Stamp Catalogue (English) – Complete free catalogue of the USA