Incumbent Democratic Sen. Jacky Rosen pulled ahead of her opponent, Republican Sam Brown, as Clark County added about 55,000 votes to its total late Wednesday.

Nevada Democrat Jacky Rosen is in a neck-and-neck battle in her bid to return to the U.S. Senate for a second term, while her party lost its slim voting majority in the upper chamber of Congress.

Polls showed Sen. Jacky Rosen leading Republican Sam Brown in Nevada as Election Day approached, but the state has historically posed polling difficulties.