With 99 percent of precincts reporting, Snyder was leading Bernero, the Democrat, 58 percent to 40 percent, the Detroit Free Press reported.
In the 7th Congressional District race, Republican Tim Walberg won with a 55 percent to 40 percent margin over Democrat Mark Schnauzer in a turnabout rematch of the 2008 race in which Schnauzer ousted the incumbent Walberg.
In suburban Detroit's 9th District House race, Democratic Rep. Gary Peters was in a tight contest with former state legislator Republican Rocky Raczkowski, leading with 49 percent to Raczkowski's 48 percent.
The dean of the U.S. House, Rep. John Dingell in his bid for a 29th term in Congress from the 15th District fought off a challenge from newcomer Rob Steele, a Tea Party-supported cardiologist whose candidacy had drawn national attention. Dingell's 100,711 votes put him well ahead of Steele's 74,815.