The resignation was expected ahead of her inauguration as the state's 57th governor on Jan. 20. Democratic Gov. Phil Murphy set the primary for Feb. 5 and the special general election for April 16.
There are already more than half a dozen Democrats vying to succeed Sherrill in New Jersey's 11th District, which she's represented since winning election in 2018. At least one Republican is running.
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The district, which includes parts of Essex, Morris and Passaic counties in northern New Jersey, had long been held by Republicans but became increasingly friendly to Democrats during President Donald Trump's first administration.
Sherrill won the governorship earlier this month, defeating Republican Jack Ciattarelli by double digits in a state that hadn't elected the same party to the governorship three straight times in six decades.
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