The 10,000 cards feature local views and events, all taken between 1900 and 1960 by the firm Chapman of Dawlish.
"What we have here is a slice of social history, taken by the same photographer, chronicling the people, streets and countryside over 60 years," commented auctioneer Trevor Vennett-Smith. He added that in his time as a postcard specialist, he had never seen a collection of this quantity before.
The collection was formed by a one-time Devon resident, and has been consigned to auction as part of a deceased estate.
Chapman of Dawlish were one of most prominent family firms of photographers at the time, and the pictures include multiple images of the same locations.
There are even some villages where the postcards in the collection outnumber the number of houses located there.
Although Devon is the main focus, there are also some postcards of North Cornwall and Dorset.
Mr Vennett-Smith said that the postcards in the collection were in above average condition, stored carefully and arranged alphabetically.
The auctioneers will be splitting up the collection, selling the best postcards as individual lots, but others will be lotted together on the basis of locality with as many as 50 cards per lot.
The first small tranche will be offered for sale at Nottingham Racecourse, Colwick Park on September 20. More will follow in their October and December sales with the total value expected to be between £10,000 and £20,000.
By Alex Capon
