Dillard, the daughter of an oil company executive, grew up in an upper middle-class home in Pittsburgh. She read voraciously; one of her favorite books was Ann Haven Morgan's The Field Book of Ponds and Streams, which she compared to the Book of Common Prayer; in painstaking detail, it instructed on the study and collection of plants and insects. She attended Hollins College in Roanoke County, Virginia, receiving both a bachelor's (1967) and a master's degree (1968). At Hollins she came under the tutelage of poet and creative writing professor Richard Henry Wilde Dillard, whom she married in 1965. She would later state that Richard taught her everything she knew about writing. Her master's thesis, "Walden Pond and Thoreau", studied the eponymous pond as a structuring device for Henry David Thoreau's Walden. Dillard's knowledge of Thoreau's works was an obvious inspiration, although critics have pointed to many differences between their two works. However, in a nod to his influence, Dillard mentions within the text that she named her goldfish Ellery Channing, after one of Thoreau's closest friends.
After graduating in 1968, she continued to live in Virginia, near the Blue Ridge Mountains, where she wrote full-time. At first she concentrated solely on poetry, which she had written and published when she was an undergraduate. She began keeping a journal in 1970, in which she recorded her daily walks around Tinker Creek. Her journals would eventually consist of 20 volumes. In 1971, after suffering from a serious bout of pneumonia, she decided to write a full-length book dedicated to her nature writings. Dillard wrote the first half of Pilgrim at her home in spring 1973, and the remaining half the following summer in a study carrel "that overlooked a tar-and-gravel roof" at the Hollins College library. She would later explain her choice of writing location as stemming from her wanting to avoid "appealing workplaces .... One wants a room with no view, so imagination can meet memory in the dark." When she first began writing the book, Dillard would only dedicate one or two hours a day to the task; by the last two months, however, she was writing nearly 15–16 hours a day.
Dillard's primary reader for Pilgrim was a Hollins professor called John Rees Moore. After finishing a chapter, she would bring it to Moore to critique. Moore specifically recommended that she expand the book's first chapter "to make clear, and to state boldly, what it was [she] was up to," a suggestion that Dillard at first dismissed, but would later admit was good advice. Previous to publication, chapters of the book appeared in publications including Harper's Magazine, The Atlantic, and The Living Wilderness. Pilgrim at Tinker Creek was published by Harper's Magazine Press in 1974, and was dedicated to Dillard's husband. Editor in chief Larry Freundlich remarked upon first reading the book: "I never expected to see a manuscript this good in my life .... The chance to publish a book like this is what publishers are here for."