According to incomplete results just before midnight, Democrat Kurt Haskell appeared to defeat Ruben Marquez to win the Democratic nomination and also will run for the new congressional seat.
Mr. Walberg's opponent was Dan Davis of Riga Township.
Michigan voters Tuesday selected party nominees for U.S. Senate, U.S. House, and state House races.
All three southeastern Michigan counties — Monroe, Hillsdale, and Lenawee — will be part of a single congressional district, the 7th, as the result of redistricting mandated by the U.S. Constitution after every decennial census.
The district also includes Branch, Jackson, and Eaton counties and part of Wash- tenaw County.
Mr. Walberg, 61, of Tipton is a former church pastor and state representative. He was elected in 2006 and was defeated by Democrat Mark Schauer of Battle Creek in 2008.
Mr. Haskell, 41, a lawyer, advocates converting to the gold standard and making deep cuts in military spending as two steps to ending the nation's dependence on deficit spending.
Mr. Marquez, 53, is a laser technician for Eaton Corp. in Jackson, chairman of the employee union there, and chairman of the Jackson County Democratic Party.
Longtime Monroe County representative, U.S. Rep. John Dingell (D., Dearborn), did not appear on the county's ballot because his congressional district was moved north.
Southeast Michigan has four state House districts, of which three had primary contests Tuesday.
The Democratic nomination in the 17th House District, which includes the city of Monroe; Monroe Township north of the River Raisin; Frenchtown, Berlin, Ash, Exeter, and London townships; and Sumpter Township and Flat Rock and Rockwood in Wayne County, was unknown just before midnight. Supporters of the three candidates — Brian David Hensley of Estral Beach, Bill LaVoy of Monroe, and Jim Pedersen of Belleville — were all watching results into the early morning hours.
Republican Anne Rossio, 29, of Carleton, a law school student at Wayne State University and a substitute teacher, was unopposed for the GOP nomination. The two winners advance to the November election.
In the 56th House District, which is the southwestern part of Monroe County, including Bedford, Dundee, Erie, Ida, LaSalle, Milan, Raisinville, Summerfield, and Whiteford townships, and part of Monroe Township, state Rep. Dale Zorn (R., Ida), the incumbent, was unopposed in the primary. Democrats Joe Astro, 61, a retired shipping/receiving clerk with Ford Motor Co., and Larry Crider, a retired police officer and sheriff's deputy, both of Dundee were fighting for the party's nomination to run against Mr. Zorn in November.
The boundaries of the new 57th House District are the same as the old 57th — all of Lenawee County except for Cambridge Township. Incumbent state Rep. Nancy Jenkins (R., Clayton) was unopposed on the Republican side. Democrats Jim Berryman, 65, a former state senator and director with the Michigan Education Association, and Harvey Schmidt of Tecumseh, a pharmacist, were waiting for results at midnight to see who would win the nomination to run against Ms. Jenkins in November.
There were no primary contests for the 58th House District, which also did not change in the reapportionment. The only candidates are Republican Kenneth Kurtz, 65, the incumbent, and Democrat Amaryllis Thomas, a retired teacher, both of Coldwater.
In the U.S. Senate election, incumbent Democrat Sen. Debbie Stabenow of Lansing, was unopposed in her primary.
The Republicans vying to oppose her are Clark Durant of Grosse Pointe Farms; Gary Glenn of Midland; former Grand Rapids judge Randy Hekman, and former U.S. Rep. Pete Hoekstra of Holland.
Early results — less than half of the state's counties reporting — showed Mr. Hoekstra with a healthy lead over the other Republicans.