Maryland Democratic incumbent Sen. Barbara Mikulski has won her bid for re-election to a fifth term in the Senate, CNN projects, beating out Republican Eric Wargotz. Projections are based on CNN analysis of exit poll data.

Alabama Republican incumbent Sen. Richard Shelby has won a fifth term to his seat in the U.S. Senate, CNN projects, beating out Democrat William Barnes.

Florida Republican Marco Rubio wins the state Senate seat vacated by retiring Republican Sen. George LeMieux, CNN projects. Rubio beat out Gov. Charlie Crist, who was running as an independent candidate, and Democratic Rep. Kendrick Meek.

Delaware Democrat Chris Coons has beat out Tea Party-backed Republican Christine O'Donnell in the race to fill Vice President Joe Biden's old U.S. Senate seat, CNN projects. Democratic Sen. Ted Kaufman, who replaced Biden, is retiring.

Former New Hampshire State Attorney and GOP nominee Kelly Ayotte has defeated Democratic nominee Paul Hodes, CNN projects, in the race to replace retiring Republican Sen. Judd Gregg.