Sheffield Council are being urged to join South Yorkshire’s three other authorities flying the White Rose Flag for Yorkshire Day on August 1.
Rotherham has the flag above its Town Hall at all times, instead of the Union Flag, while Doncaster will be hoisting it above Mansion House and Barnsley Council above the Town Hall on Yorkshire Day.
But they are among just seven of 70 councils in the region making the gesture for the county’s day of celebration.
In a letter to councils not displaying the flag, the Yorkshire Devolution Movement said: “Yorkshire has a unique and different cultural identity.
“We believe this clear cultural link between us unites our county, and that flying our flag is only a small ask.
“It is very disappointing that so few councils will be flying the Yorkshire flag on Yorkshire Day and that even fewer intend to fly it all the year round.
“This suggests an apparent lack of pride many councils have in the county and all this barely a year on from when Yorkshire sportsmen and women did so magnificently in the Olympics.
“It is hard to imagine such disinterest in Scotland and Wales.”