Labour's Dan Jarvis is the favourite to become Yorkshire's first directly elected mayor in the May 3 vote after winning his party's nomination last week, while the Conservatives have yet to announce a candidate.
A public awareness campaign has now been launched across social media, radio, and street posters to give residents in Barnsley, Doncaster, Rotherham and Sheffield information on the election and how to vote in it.
The campaign will end on April 11 ahead of the vote.
Dave Smith, managing director of the Sheffield City Region said: "I urge all residents in South Yorkshire to make sure you are registered and able to vote in the election of a Sheffield City Region Mayor on May 3."
Mr Jarvis's candidacy could spark a row within Labour, as the party's ruling body has passed a motion which states he cannot continue as Barnsley Central MP and work as Sheffield City Region mayor.
But the former soldier has argued the Sheffield City Region role is different to other mayoralties as it will initially have "no power and no resources", insisting he could use a dual role to leverage maximum influence in Westminster to get a good deal for the area and build momentum for wider Yorkshire devolution.