"Our society does better when more people vote, when more people are engaged," Schall said.
Del. Heather R. Mizeur, a contender for the Democratic nomination, planned two community meetings to mobilize organizers for the early voting period, said Steven Hershkowitz, a campaign spokesman.
Hershkowitz said the campaign is "working to make sure voters come out in full force during early voting and Election Day."
On the GOP side, businessman and activist Larry Hogan launched a two-week bus tour, which will stop in Baltimore and each of the Maryland counties.
"We're encouraging people to get out and vote at each stop along the way," said Adam Dubitsky, a spokesman for Hogan.
Other Republican candidates for governor, Harford County Executive David R. Craig, Charles County business executive Charles Lollar and Del. Ron George of Anne Arundel, also are working to mobilize supporters.
But some political observers question whether offering early voting is worth the investment.
Todd Eberly, an assistant professor of political science at St. Mary's College, said turnout in the 1994 primary was about 40 percent.
Eberly said he expects turnout for this year's primary will be half that.
"Early voting is going to cost the counties millions, which may raise questions about whether early voting in a primary is really worth it if no one shows up," Eberly said.
The General Assembly attempted to create early voting opportunities in 2005, but the initiative was vetoed by then-Gov. Robert L. Ehrlich Jr. Lawmakers overrode the veto the next year, but opponents objected in court.
The Court of Appeals ruled in August 2006 that early voting violated the Maryland Constitution, and it was canceled. The General Assembly amended the constitution in 2007, and voters ratified the change in 2008. Last year, lawmakers decided to offer more sites, longer hours and an extra day.
Baltimore Sun reporters Erin Cox and Michael Dresser contributed to this article.
Expanded early voting options
•Maryland will offer 63 locations for voters to cast ballots during an extended early voting period that begins Thursday.
•The polls will open daily from 10 a.m. to 8 p.m. through June 19.
For more information, visit http://www.elections.state.md.us.