Ada Calhoun is an American nonfiction writer. She is the author of St. Marks Is Dead, a history of St. Mark's Place in East Village, Manhattan, New York; Wedding Toasts I’ll Never Give, a book of essays about marriage; Why We Can't Sleep, a book about Generation X women and their struggles, and Also a Poet, a memoir about her father and the poet Frank O’Hara. She has also been a critic, frequently contributing to The New York Times Book Review; a co-author and ghostwriter, the New York Times having reported that she collaborated on the 2023 Britney Spears memoir The Woman in Me; and a freelance essayist and reporter. A Village Voice profile in 2015 said: "Her CV can seem as though it were cobbled together from the résumés of three ambitious journalists."

St. Marks Is Dead: The Many Lives of America's Hippest Street is a nonfiction book by Ada Calhoun about the history of St. Mark's Place, a three-block stretch of East Village, Manhattan. Calhoun, who grew up on the street, shows how disillusioned bohemians of every era have declared "St. Marks Is Dead" when their era on the street passed. The book was released on November 2, 2015, by W. W. Norton & Company. It was named by many publications one of the best books of 2015.