McMahon stepped into the job following accusations in a report by the Howard County Office of Human Rights that Sheriff James Fitzgerald discriminated against a top lieutenant and berated other employees using racist language, claims he denied.
Fitzgerald resigned in 2016 and Gov. Larry Hogan appointed McMahon to fill the final years of the term.
In addition to providing courthouse security and prisoner transportation, the sheriff’s office conducts patrols, serves warrants and handles domestic abuse cases.
The planned January retirement of Howard County’s top prosecutor, Dario Broccolino, provided fresh opportunities in the race for state’s attorney.
Broccolino, a Democrat who has been in office for nearly 12 years, endorsed his deputy, Kim Yon Oldham, a Republican. She was challenged by Democrat Rich Gibson, a supervising prosecutor in Baltimore City’s state’s attorney office.
Gibson beat Oldham 80,764 to 49,535, according to unofficial results.