Whom she plays: Piper Chapman, a woman who gets sent to prison for once carrying drug money 10 years prior.
Where you know her from: Nurse Veronica Flanagan Callahan on Mercy, Beth in The Lucky One, Dagny Taggart in Atlas Shrugged: Part I.
Where you'll see her next: She's starring in Stay, based on the novel by Aislinn Hunter.
Laura Prepon
Whom she plays: Alex Vause, Piper's ex-girlfriend and drug runner.
Where you know her from: Donna Pinciotti on That '70s Show, Hannah Daniels on October Road, Chelsea Newman on Are You There, Chelsea?
Michael Harney
Whom he plays: Sam Healy, Piper's counselor in prison.
Where you know him from: Pete Jensen in Erin Brockovich, Steve on Deadwood, Det. Mitch Ouellette on Weeds.
Michelle Hurst
Whom she plays: Miss Claudette Pelage, Piper's roommate.
Where you know her from: Nurse in Stepmom, Dorothy Washington in Sherrybaby, Theater Manager in Frances Ha.
Kate Mulgrew
Whom she plays: Galina "Red" Reznikov, an inmate who also serves as the prison chef.
Where you know her from: Captain Kathryn Janeway on Star Trek: Voyager, Mary Ryan on Ryan's Hope, Kove on NTSF:SD:SUV::.
Where you'll see her next: As Edith Morse Robb in 1920s period piece Drawing Home.
Whom he plays: Larry Bloom, Piper's struggling writer fiancé.
Where you know him from: Jim Levenstein in the American Pie series, Ben Parr on Mad Love, Dylan Stack on The Good Wife.
Where you'll see him next: He's the voice of Leonardo on Nickelodeon's Teenage Mutant Ninja Turtles.
Danielle Brooks
Whom she plays: Tasha "Taystee" Jefferson, an inmate and Poussey's best friend.
Where you know her from: Raimy in Modern Love.
Samira Wiley
Whom she plays: Poussey Washington, an inmate and Taystee's best friend.
What you know her from: Gina on Unforgettable, Tina in The Sitter, Asha in Being Flynn.
Where you'll see her next: As Agent Annie Bell in Rob the Mob, which is currently filming.
Natasha Lyonne
Whom she plays: Nicky Nichols, a recovering addict in prison.
Where you know her from: Jessica in the American Pie series, Vivian Abromowitz in Slums of Beverly Hills, Megan Bloomfield in But I'm a Cheerleader.
Where you'll see her next: As Yael in the thriller 7A and Gloria in The Quitter.
Pablo Schreiber
Whom he plays: George "Pornstache" Mendez, a corrupt prison guard.
Where you know him from: Nick Sobotka on The Wire, Johnny Leary on Lights Out, Demetri Ravitch on Weeds.
Where you'll see him next: As Staff Sergeant Donovan in Fort Bliss and Bryan Macy in The Dramatics.
Laverne Cox
Whom she plays: Sophia Burset, an inmate and transsexual woman.
Where you know her from: A contestant on I Want to Work for Diddy, the host of TRANSform Me, Sex Worker on Bored to Death.
Where you'll see her next: She's starring as Chardonnay in Grand Street.
Yael Stone
Whom she plays: Lorna Morello, an inmate who drives the van and dates Nicky.
Where you know her from: Stacy in Me Myself I, Ann-Marie Preston on All Saints, Linda on Spirited.
Nick Sandow
Whom he plays: Joe Caputo, a prison employee.
Where you know him from: Father Dan on How to Make It in America, Lt. Alex Bello on Blue Bloods, Waxey Gordon on Boardwalk Empire.
Maria Dizzia
Whom she plays: Polly Harper, Piper's best friend.
Where you know her from: Katie in Martha Marcy May Marlene, Woman Subletter in Lola Versus, Delores on Louie.
Where you'll see her next: As Allison McColl in Captain Phillips, based on a true story, and Mary Jane Longo in True Story, also based on a true story, naturally.
Nick Stevenson
Whom he plays: Pete Harper, Polly's husband.
Where you know him from: Ken in The Contenders, several short films.
Where you'll see him next: As Cooper in Extinction: Patient Zero and Bobby Weldon in dramedy Isn't It Delicious.
Uzo Aduba
Whom she plays: Susanna "Crazy Eyes" Warren, an inmate who takes a liking to Piper.
Where you know her from: Cafeteria Lady in the short Sing Along.
Catherine Curtin
Whom she plays: Wanda Bell, a prison corrections officer.
Where you know her from: Fran on Guiding Light, Betty on The Naked Brothers Band, Leigh-Anne Black in Extremely Loud and Incredibly Close.
Where you'll see her next: As an FBI agent in Martin Scorsese's The Wolf of Wall Street.
Dascha Polanco
Whom she plays: Dayanara "Daya" Diaz, an inmate in a relationship with a prison guard.
Where you know her from: Estella on Unforgettable.
Where you'll see her next: As Carmel in Gimme Shelter starring Vanessa Hudgens.
Matt McGorry
Whom he plays: John Bennett, a prison guard in a relationship with Daya.
Where you know him from: Grey Malcolm in Thursday, Officer Sam Klecko on Elementary, several CollegeHumor shorts.
Elizabeth Rodriguez
Whom she plays: Aleida Diaz, Daya's mother and fellow inmate.
Where you know her from: Gina Calabrese in Miami Vice, Carmen Morales on All My Children, Detective Carolina Rivera on Prime Suspect.
Where you'll see her next: As Rita Sierra in Glass Chin, and she's featured in crime drama Animal Rescue.
Taryn Manning
Whom she plays: Tiffany "Pennsyltucky" Doggett, an inmate who tries to preach to and heal other inmates.
Where you know her from: Mimi in Crossroads, Nola in Hustle & Flow, Mary Ann McGarrett on Hawaii Five-0.
Where you'll see her next: As Patricia Rose in A Winter Rose, Leslie in Heaven's Rain, and Kamila in Man Without a Head, among other projects.
Vicky Jeudy
Whom she plays: Janae Watson, an inmate who arrives at the same time as Piper.
Where you know her from: She's been in various short films, including Bottom Feeder, Living Peterson, and Addiction.
Madeline Brewer
Whom she plays: Tricia Miller, an addict who relapses in prison.
Where you know her from: This is her first role.
Lea DeLaria
Whom she plays: Carrie "Big Boo" Black, a butch inmate.
Where you know her from: Angie in Edge of Seventeen, Professor Delbert Fina on One Life to Live, a lengthy stand-up comedy career.
Beth Fowler
Whom she plays: Sister Ingalls, an activist nun in prison.
Where you know her from: Choir Nun in the Sister Act series, Mistress of Ceremonies on Gossip Girl, several Broadway shows.
Lin Tucci
Whom she plays: Anita De Marco, Piper's first roommate.
Where you know her from: Henrietta "Mama" Bazoom in Showgirls, Aunt Louise in Brooklyn Rules, Sheila in How to Seduce Difficult Women.
Constance Shulman
Whom she plays: Yoga Jones, an inmate who teaches yoga.
Where you know her from: The voice of Patti Mayonnaise on Doug, Missy in Fried Green Tomatoes, Shelly Ray on The Faculty.