Their job is to hold federal politicians to account and sniff out stories on Parliament Hill — and they've been doing it for a century and a half.

This spring, the band of reporters who make up the Parliamentary Press Gallery will mark 150 years of political journalism with a book on the gallery's long, storied history.

If you do the math, you'll notice something curious: the founding of the press gallery actually predates Canada's confederation in 1867 by one year.

"Isn't that interesting? Well, it's because the buildings opened in 1866," said Jennifer Ditchburn, a reporter with the Canadian Press and a member of the group that's putting the book together.

"And so it was the last sitting of the legislative assembly of the Province of Canada, which was basically Ontario and Quebec together. So when the buildings opened in June of 1866, there was a press gallery."

press gallery offices 1948

From 1948, a glimpse inside the parliamentary press gallery offices — and at some of the fancy hats of a bygone era. (Library and Archives Canada)

In those early days, reporters were aligned closely with a particular party and the gallery's seating arrangements were based on whether you supported the Conservatives or the Liberals, Ditchburn told Ottawa Morning host Robyn Bresnahan on Monday.

The gallery's demographic makeup was also considerably less diverse, and it wasn't until the 1920s that the gallery officially welcomed its first female member, Manitoba reporter Genevieve Lipsett-Skinner.

"It's been remarkable to look back at the history and see how many things have changed, especially for the better," said Josh Wingrove, the book's co-editor and a reporter with Bloomberg News.

"The one that jumps out is that it's not just a bunch of white Anglophone men anymore, thank god."

Those interested in a sneak preview of the forthcoming book can visit the Press Gallery 150 Facebook page, which features a selection of current and archival photos that could make their way into the final product.

Ditchburn said anyone with photos or archival materials related to the gallery can contact the group through their Facebook page.

"I just have this feeling that there's way more stuff out there," she said.