In early April 1951, Kerouac sat down at a typewriter in a Manhattan apartment and barely got up for three weeks. What came out was a single roll of paper roughly 120 feet long, taped together sheet by sheet, with the whole story running down it in one unbroken column. That roll was a draft, and the book most people read arrived years later.

The Direct Answer
He typed the first draft in about three weeks on one continuous 120-foot scroll.
Kerouac taped sheets of paper into a single roll so he never had to stop and reload the typewriter, a manuscript now published as On the Road: The Original Scroll.

The Roll of Paper That Became a Legend

The details are well recorded. Starting in early April 1951, in the apartment he shared with his second wife, Joan Haverty, on West 20th Street in Manhattan, Kerouac fed long sheets of tracing paper through his machine, trimmed them to width, and taped them end to end. He typed single-spaced, with almost no margins and no paragraph breaks, so nothing on the page would interrupt him. By the time he stopped, close to three weeks later, the taped roll ran to about 120 feet.

The point of the scroll was momentum. Every time a writer reaches the bottom of a page, a fresh sheet has to go in, and Kerouac wanted none of that friction. He had already lived the road trips with Neal Cassady and turned them over in his mind for years, so the writing came in a rush, in the long breathless sentences he later compared to a jazz solo. Coffee kept the sessions running. Benzedrine was part of this period of his life as well, common in his circle at the time, and it belongs in the record even if it adds nothing to admire in the work itself.

Jazz and bop, in the sense of a, say, a tenor man drawing a breath and blowing a phrase on his saxophone, till he runs out of breath, and when he does, his sentence, his statement's been made.

Jack Kerouac, The Paris Review, 1968

The Scroll Was a Draft. The Book Came Later.

This is the fact that gets lost. The 120-foot roll was Kerouac's first full draft, not the finished novel. Over the next six years, he and his editors reworked the manuscript and swapped the real names for invented ones before Viking published On the Road in 1957. In the scroll the people still wore their own names, so Neal Cassady was simply Neal Cassady; by the time the book appeared he had become Dean Moriarty, and Kerouac himself was Sal Paradise. The famous three-week burst produced the raw material, and a lot of shaping happened afterward. Kerouac loved the image of pure spontaneity, yet scholars who have studied the scroll describe a careful craftsman who kept going back to his work.

The roll itself survived. It has been exhibited around the country, published in full, and sold at auction for millions, which tells you how much the object came to mean. What it should not do is convince you that a masterpiece falls out of a person in one sitting.

For the wider picture, see the full Jack Kerouac writing routine, including his night sessions and the candle he wrote by.

What You Can Steal