Flaxley was once a major industrial centre. The Forest of Dean was an important medieval ironworking region, and the earliest forge in Flaxley is recorded in the 12th century. Westbury Brook was the site of five water mills, and at Gun's Mill by Flaxley was one of the main gun foundries of the English Civil War era. A blast furnace was built there in 1629. Today, Flaxley offers a pleasant picturesque wooded scene and is difficult to imagine it any other way, but it has a strong industrial past, notably of iron furnaces, forges and water mills. The earliest known forge was present as early as 1150 and at least five mills have been identified as utilising the waters of Westbury Brook which runs down the valley. The earliest and most famous industrial site is Gun's Mill, (at SO67519), now a guesthouse. This blast furnace, was built by Sir John Wintour, operated between 1629 to 1743 and was named after William Gunne, the owner of an earlier mill on the site. Gun's Mill was used primarily for armament production and in 1629, the Crown ordered that 610 guns were to be made there and sent to the Netherlands, but many were subsequently used by both sides in the English Civil War. The furnace was destroyed by order of Parliament in 1650 but it was rebuilt in 1683 and remained in use until c.1743 when it became a paper mill. The latter closed in 1879 but several of the furnace's buildings remain and the site is now a scheduled monument as it is the finest remaining example of a charcoal blast furnace from this period in the country.