The Great Fire of Northampton occurred on 20th September 1675. Destroying three quarters of Northampton, it was one of the most disastrous events in the history of the town.

The blaze was caused by a spark from an open fire in a house on St Mary’s Street. Like many other great fires in medieval England, it spread easily due to the narrow roads and thatched, wooden houses. In Northampton, it was quickened by a strong westerly wind. Furthermore, goods packed on the Market Square, along with corn stacks, malt, oil, and tallow (animal fat used in lighting) stored in buildings fuelled the flames.

According to a witness, a country minister, the blaze was "more furious and destructive," than the Great Fire of London. Many local people trapped by the fire were forced to escape through the Welsh House, which did not catch fire. Most had lost their homes. By the end of the day, the fire had destroyed 600 homes and made 700 families homeless. The estimated damage was over £150,000 (around £12m today).

In the following days, people across Northamptonshire and beyond rallied to support those affected. Many individuals and villages sent donations and local gentry housed the homeless. King Charles II donated over 1000 tons of timber to reconstruct All Saints Church and halved the town’s taxes for seven years.

A special Act for rebuilding Northampton was rushed through Parliament in six weeks, largely due to pressure from Lord Northampton at Castle Ashby. Consequently, the main streets were widened and new houses were built with slate roofs.