Thetford is a town in Orange County, of the Woodstock-Quechee region and is home to Thetford Academy, Vermont's oldest secondary school. The town includes the villages of East Thetford, North Thetford, Thetford Hill, Thetford Center, Rices Mills and Post Mills. The Post Mills Church and the Vermontasaurus are cultural attractions in the village of Post Mills.

The town was chartered in 1761 and named in honor of Augustus Henry Fitzroy, 3rd Duke of Grafton, 4th Earl of Arlington, 4th Viscount Thetford, a distant cousin of the king who become Prime Minister in 1768.

Some notable people of the area include: William Closson, an artist; John Eaton, a brigadier general; Anne Lindbergh, an author & the daughter of Charles Lindbergh & Anne Morrow Lindbergh; Gustavus Loomis, a brigadier general; Harvey Newcomb, a clergyman & writer; Grace Paley, a National Book Award winning fiction writer & poet; Noel Perrin, an essayist; Annie Proulx, an author; James S. Shapiro, a professor; Henry Wells, co-founder of Wells Fargo & American Express; and Dean Conant Worcester, a zoologist, public official, & authority on the Philippines.