Canberra Museum and Gallery has purchased the more than 3500 images, taken from the 1920s to the 1990s, that relate to Canberra and the region.

The photographs were part of a huge trove of images sent by what was then Fairfax Media to the United States to be digitised in 2013.

The company undertaking the work was liquidated soon after, and the photographs languished in a warehouse in Arkansas, until the California-based Duncan Miller Gallery acquired them.

The Canberra gallery arranged to buy the portion of the collection relating to Canberra, 3600 images in all, costing $20,000, or about $5 per photograph.

The mostly black-and-white images include horse-drawn carts on suburban streets, community meetings, protests and street performers.

There are also weekend scenes at some of the city's popular riverside reserves, views of what was then the very modern Monaro Shopping Mall in Civic, and newly built 1950s housing.

There's even a photo of Canberra Times staff modelling their new uniforms outside the newspaper's old office in Braddon in 1978.

Gallery director Shane Breynard said the photographs would fill many gaps in the ACT historical and social history collection.

"Not only does this collection reflect the development of our city and community over a seventy-year period, it also documents an era before the advent of online technologies, when the photographic image on the newspaper’s printed page played a more central role in shaping and reflecting the values of our community than it does today," he said.

"The collection undoubtedly includes the work of some of Australia’s most talented photo journalists. The task of identifying and acknowledging each photograph’s authorship, and establishing image licence agreements where necessary, will be ongoing."

Curator Rowan Henderson said it wasn’t until late 2018 that the gallery took steps to inquire about Canberra-based content.

The gallery sent them enticing images of a row of battered office files - clearly used frequently in various busy newsrooms - with Canberra labels.

"We got more and more excited as we realised what was going to be in the collection," Ms Henderson said.

"This was obviously a working archive for the press, and so things are misfiled.

"The bones are there in terms of the categories, but there's still obviously a lot of work to do in terms of re-cataloguing them."

Arts Minister Gordon Ramsay said the acquisition was a "real win" for the gallery, and for Canberra historians.

"The collection provides a rich new resource to connect with and research the history of our region," he said, adding that the gallery would be working with conservation students from the University of Canberra to help catalogue the collection.

"Behind the photographic image the comments, captions, stamps and crop lines on the back of each print also tell fascinating stories which will be captured in the cataloguing process," he said.

The first major exhibition of photographs from the collection will be to mark Canberra Day in March next year.