Mercer County Elections Director James R. Bennington predicts 20 percent of the county's registered voters will turn out to the polls today for the primary election, but the percentage should be higher in the Shenango Valley.

A pair of races -- Democratic contests for governor and state House -- should attract a large number of voters to the polls in the valley, where Democrats outnumber Republicans about 7 to 3, Bennington said.

Hermitage school board member Jim Lumpp is challenging 11-term state Rep. Michael C. Gruitza for the Democratic nomination to represent the Shenango Valley-based 7th District in Harrisburg, while former Philadelphia Mayor Ed Rendell and state Auditor General Bob Casey Jr. are battling for the Democratic nomination in the gubernatorial race.

In southeastern Mercer County's 8th District, Republican freshman state Rep. Dick Stevenson, Grove City, faces a primary challenge from Stevie Mick of Zelienople. The winner of that race will face Democrat Mark Lauer of Butler -- who is running unopposed -- in the fall.

Democratic voters from Farrell, Wheatland, West Middlesex, Shenango Township and part of Hermitage also will get to choose between a pair of congressional candidates, Stevan Drobac and Mark Purcell, in a U.S. House race in the 4th District. Republican incumbent U.S. Rep. Melissa Hart is unopposed. To reflect U.S. Census changes, the district -- which stretches south into Allegheny County -- was redrawn this year to include part of Mercer County.

Outside the Shenango Valley, where Republicans outnumber Democrats, there are few contested races to attract voters, Bennington said.

Republican voters from across the county will pick three state committee members from a field of four candidates. There is no GOP race for governor -- state Attorney General Mike Fisher is unopposed.

Republican U.S. Rep. Phil English -- whose 21st District was redrawn and renumbered the 3rd -- is unopposed in his bid for a fifth term representing northwest Pennsylvania in Washington, and 17th District state Rep. Rod Wilt, also a Republican, is unopposed in his bid for a fourth term representing northern Mercer County and part of Crawford County.