The town's name itself is a landscape description in Old English: aesc-burna-tun, the settlement by the stream where ash trees grow. It was recorded as Essebretone in the Domesday Book of 1086. For most of the Middle Ages Ashburton was a stannary town - one of only four in Devon - the legal centre where tin from the Dartmoor mines was weighed, stamped, and taxed before it could be sold. Tin was a serious business. Devon and Cornwall produced most of the tin used in medieval and early modern Europe, and the stannary courts had their own laws and customs. Ashburton sits on the south-southeastern edge of Dartmoor, with the high granite tors rising behind it and the rich farmland of the South Hams stretching south toward the sea. The 15th-century parish church of St Andrew has a tall tower visible from the moor, with stained glass by Charles Eamer Kempe and carved oak by Herbert Edmund Read.

Sometime in the 17th or 18th century, an Ashburton brewer was making something he called Ashburton Pop - a sparkling beverage, possibly a kind of champagne-style fermented drink, that was famous well beyond the town. People wrote about it. Visitors asked for it. The corks were celebrated and at least one cork survives in a private collection as a small piece of history. Then in 1765 the brewer died, and his recipe died with him. No one ever produced Ashburton Pop again. The town still talks about it. It is the kind of small, specific, unprovable loss that gives an English market town its character: not the big famous things but the local mystery, the recipe that no one wrote down, the question that can no longer be answered.

In January 1646, after Oliver Cromwell's cavalry surprised and routed the Royalist camp at nearby Bovey Heath, the defeated Royalists fled south through Devon. Ashburton became a temporary refuge for some of them. It was a brief military moment - the Parliamentary army of Sir Thomas Fairfax was already marching south, the Royalist garrisons in the area were abandoning their positions, and Dartmouth would fall to Parliament within weeks. But for a few days in midwinter, Ashburton's narrow streets and old inns held Royalist soldiers trying to reorganise. The First English Civil War ended that summer. The town went back to its tin and its wool. The market continued. The houses on East Street that watched those soldiers pass are mostly still standing.

Ashburton Carnival is one of the oldest in Devon and possibly the oldest still running, with written records back to 1891 and an origin in the mid-1880s when it was started to raise funds for a new town hospital. The carnival still happens every year. The town still annually appoints a portreeve, an Anglo-Saxon office surviving in only a handful of English towns. It supports two pubs and six restaurants and cafés. It is home to Sands School, founded in 1987 as England's second democratic school, where pupils and staff vote together on how the school is run. It is home to the Ashburton Cookery School. The Buckfastleigh, Totnes and South Devon Railway opened a terminus here on 1 May 1872, and although the line closed in 1962, the old route is now partly preserved as a heritage railway. William John Wills, who in 1860-61 served as second-in-command on the doomed Burke and Wills expedition to cross Australia south to north, attended the grammar school in Ashburton. Stevie Smith, the poet who wrote 'Not Waving but Drowning,' died here in 1971. Ollie Watkins, the England international footballer, was educated at South Dartmoor Community College down the road. The town keeps producing them.