Democratic congressional hopeful Joe Cunningham had a very good day in Charleston County, the largest voting bloc in South Carolina's 1st Congressional District, according to an exit poll.

The poll showed Cunningham with a 2-1 edge over Republican Katie Arrington in the county.

Both are vying for the seat currently held by U.S. Rep. Mark Sanford, who lost to Arrington in the June GOP primary.

Even if the numbers are on target in Charleston County, Arrington could still prevail. The poll didn't survey voters in the district's other counties, such as Dorchester, Beaufort and Colleton, which have had more reliably Republican voting patterns in recent years.

The poll was done by students at the University School of the Lowcountry, and it focused on Charleston County, plus Daniel Island in Berkeley County because those precincts are closest to its Mount Pleasant campus.

The students, who ranged from grades 3 through 12, surveyed voters leaving local precincts Tuesday. They have had a remarkably accurate track record in previous elections.

The students polled at 26 precincts in Charleston County, and Cunningham won 25 of them, according to Head of School Jason Kreutner. Cunningham also beat Arrington on Daniel Island by a 3-2 margin.

Meanwhile, the poll showed Democratic gubernatorial candidate James Smith also had a 64-32 edge over Republican incumbent Henry McMaster in Charleston County and Daniel Island. However, news outlets already have forecast McMaster winning statewide.

The poll also showed Democratic Attorney General candidate Constance Anastapoulo with a 62-37 lead over GOP incumbent Attorney General Alan Wilson in Charleston-area precincts.

And it predicted the constitutional question to move the S.C. Superintendent of Education from an elected office to a gubernatorial appointment will go down in flames. The poll showed it losing here by 64-36.

Meanwhile, the poll also showed Charleston County School Board incumbents Kate Darby, Eric Mack and Cindy Bohn Coats likely to win their re-election bids, with the fourth seat going to former J.B. Edwards Elementary Principal Jake Rambo.

If Cunningham prevails over Arrington, it would mark the first time the coastal congressional seat has been won by a Democrat in 40 years.  

Almost 30 percent of Charleston County voters polled said they have moved here within the past five years.

Reach Robert Behre at 843-937-5771. Follow him on Twitter @RobertFBehre.