The town's name comes from the Anglo-Saxon for "rocky hill," which is exactly what it is. Clitheroe grew up around a 39-metre limestone outcrop in the Ribble Valley, where Norman lords found the perfect site for a castle that could control the pass between the Pennines and the Forest of Bowland. The earliest existing charter dates from 1283, granted by Henry de Lacy, Earl of Lincoln, confirming rights his forebears had given decades earlier. Through the Honour of Clitheroe, the town's de Lacy lords held one of the largest feudal estates in the north of England, eventually absorbed into the Duchy of Lancaster. The Battle of Clitheroe was fought somewhere near here in 1138, during the Anarchy, when a Scottish force under William fitz Duncan defeated an English army that had marched up the Ribble. Most of the town's medieval fabric has gone, but the castle keep on its limestone hill is still the visual centre of everything.

Clitheroe and the wider Ribble Valley have, by various measures over the past decade, been named the healthiest and happiest place to live in the United Kingdom. The Sunday Times has listed the area in its best-places-to-live rankings for 2017, 2018, and 2024. The town has five supermarkets, three jewellers, and a small but resilient set of independent shops along Castle Street and Moor Lane. Heidelberg Materials - formerly Hanson Cement, known locally as Castle Cement - has run the Ribblesdale plant since 1936; it celebrates its ninetieth anniversary in 2026. Johnson Matthey, the international chemicals firm, bought ICI's local plant in 2002 for a reported £260 million. Dugdale Nutrition, the family-owned animal feed producer, traces its origins to John Dugdale trading from Waddington Post Office in 1850. The economy is rural-industrial in a way that has not vanished elsewhere in Lancashire.

St Mary Magdalene is the medieval parish church. St James' and St Paul's at Low Moor are the other Anglican congregations. The Roman Catholic church of St Michael and St John on Lowergate serves a Catholic population whose secondary school, St Augustine's at Billington, sits a few miles south. There is a Trinity Methodist church on the edge of Castle Park, a United Reformed Church, the Clitheroe Community Church, a Salvation Army citadel, a Friends meeting house opened in 2017, and since 2014 a multi-faith centre with a Muslim prayer room in a former church on Lowergate. The castle on the hill has its famous hole in the wall - originally ordered by Parliament's slighting commissioners in 1649, embellished by local legend into a Devil's missile or Cromwell's cannonball. The current MP is Jonathan Hinder, first elected for Labour in 2024 - the first Labour candidate to win in Clitheroe since the 1945 landslide.

Captain James King, born here in 1750, sailed with Captain Cook on his third and final voyage; after Cook's death at Kealakekua Bay, King wrote the official journal of the return. Cyril Washbrook played 37 Test matches for England and 592 first-class cricket games between the wars. Sir Derek Spencer was Solicitor General. Director Ian Sharp made Who Dares Wins and the action sequences of GoldenEye. Michael Bisping, raised in Clitheroe, became in 2016 the first British UFC world champion, knocking out Luke Rockhold in the first round to take the middleweight title; he was inducted into the UFC Hall of Fame in 2019. Jon Schofield won Olympic medals in canoeing in 2012 and 2016. Samantha Murray took silver in modern pentathlon at London 2012. Clitheroe Royal Grammar School and Ribblesdale High School are the two main secondaries; the town is twinned with Rivesaltes in France.