Sen. Ted Cruz (R-Texas) -- Announced March 23, 2015(01 of22)
Open Image ModalSen. Rand Paul (R-Ky.) -- Announced April 7, 2015(02 of22)
Open Image ModalFormer Secretary Of State Hillary Clinton -- Announced April 12, 2015(03 of22)
Open Image Modal (credit:Andrew Burton via Getty Images)
Sen. Marco Rubio (R-Fla.) -- Announced April 13, 2015(04 of22)
Open Image ModalSen. Bernie Sanders (I-Vt.) -- Announced April 30, 2015(05 of22)
Open Image Modal (credit:ASSOCIATED PRESS)
Ben Carson -- Announced May 4, 2015(06 of22)
Open Image ModalCarly Fiorina -- Announced May 4, 2015(07 of22)
Open Image ModalFormer Arkansas Gov. Mike Huckabee (R) -- Announced May 5, 2015(08 of22)
Open Image ModalFormer Sen. Rick Santorum (R-Pa.) -- Announced May 27, 2015(09 of22)
Open Image ModalFormer New York Gov. George Pataki (R) -- Announced May 28, 2015(10 of22)
Open Image ModalPataki dropped out of the race on Dec. 29, 2015. (credit:ASSOCIATED PRESS)
Former Maryland Gov. Martin O'Malley (D) -- Announced May 30, 2015(11 of22)
Open Image ModalSen. Lindsey Graham (R-S.C.) -- Announced June 1, 2015(12 of22)
Open Image ModalGraham dropped out of the race on Dec. 21, 2015. (credit:Jessica McGowan via Getty Images)
Former Rhode Island Gov. Lincoln Chafee (D) -- Announced June 3, 2015(13 of22)
Open Image ModalChafee ended his campaign on Oct. 23, 2015. (credit:Win McNamee via Getty Images)
Former Texas Gov. Rick Perry (R) -- Announced June 4, 2015(14 of22)
Open Image ModalFormer Florida Gov. Jeb Bush (R) -- Announced June 15, 2015(15 of22)
Open Image ModalBusiness Mogul Donald Trump (R) -- Announced June 16, 2015(16 of22)
Open Image Modal (credit:Christopher Gregory via Getty Images)
Louisiana Gov. Bobby Jindal (R) -- Announced June 24, 2015(17 of22)
Open Image ModalJindal dropped out of the race on Nov. 17, 2015. (credit:Darren McCollester via Getty Images)
New Jersey Gov. Chris Christie (R) -- Announced June 30, 2015(18 of22)
Open Image ModalFormer Sen. Jim Webb (D-Va.) -- Announced July 2, 2015(19 of22)
Open Image ModalWisconsin Gov. Scott Walker (R) -- Announced July 13, 2015(20 of22)
Open Image ModalFormer Virginia Gov. Jim Gilmore (R) -- Declared July 29, 2015(21 of22)
Open Image ModalFormer New Mexico Gov. Gary Johnson (L) -- Announced Jan. 6, 2016(22 of22)
Open Image ModalJohnson will seek the Libertarian Party's nomination. (credit:Mark Wilson/Getty Images)