Orange County’s two largest automakers, Hyundai Motor America Inc. and Kia Motors America Inc., continued to outpace their peers in September.

The two manufacturers broke records last month even as other automakers with U.S. operations based in Orange County saw sales slow.

Hyundai, which has temporary headquarters in Costa Mesa while its Fountain Valley campus is being built, sold 60,025 vehicles in September. That’s up 15.3% from a year earlier and the 25th-straight month of year-over-year monthly increases.

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Irvine-based Kia sold 48,105 vehicles, up 35.1% from a year earlier for a 25th-straight month of record-breaking sales.

Sales from automakers elsewhere in the county weren’t as robust.

Brea-based American Suzuki Motor Corp. sold 1,921 vehicles in September, down 5.2% from a year ago.

Mazda North American Operations of Irvine sold 24,135 vehicles, a decline of 5.4% from a year earlier.

Cypress-based Mitsubishi Motors North America Inc. saw the steepest drop in sales last month. The automaker sold 4,806 vehicles, down 17.2% from a year ago.

“Comparisons to last year’s total sales are still being slightly affected by some models that ended their production last year,” said Mitsubishi Chief Executive Yoichi Yokozawa in a statement. “Obviously, this effect will have a diminishing impact over the next few months.”

September vehicle sales climbed 12.8% to 1.2 million vehicles nationally, according to Woodcliff Lake, NJ-based Autodata Corp.’s online industry researcher Motor Intelligence.

That puts automakers on track to see nearly 15 million vehicles sold by the end of the year, according to Motor Intelligence.