Mastriano, who promotes Trump's claims of a stolen 2020 election, will face state Attorney General Josh Shapiro, who ran unopposed for the Democratic nomination.
GOP voters in Pennsylvania picked state Sen. Doug Mastriano as their candidate for governor, according to the AP. Mastriano has touted far-right views and election lies, drawing Trump's endorsement.
A businessperson seeking office for the first time, Ashley Kalus, has won the Republican primary for Rhode Island governor, defeating a rival who has served time in state prison.
In South Dakota, Trump-endorsed Gov. Kristi Noem wins the primary for governor, as does Republican Sen. John Thune, an adversary of the former president.
View live updates on electoral votes by state for presidential candidates Joe Biden and Donald Trump on ABC News. Senate, House, and Governor Election results also available at ABCNews.com