Wath can trace its existence back to Norman times, having an entry in the Domesday Book as Wad. For hundreds of years it remained a quiet rural settlement astride the junction of the old Doncaster-Barnsley and Rotherham-Pontefract roads, the latter a branch of Ryknield Street. North of the town was the ford of the River Dearne by this road that gave the town its name: the origin of its name has been linked to the Latin vadum and the Old Norse vath (ford or wading place). The town received its Royal Charter in 1312 – 13 entitling it to hold a weekly Tuesday market and an annual two-day fair, but these were soon discontinued. The market was revived in 1814.
Until the mid-19th century the town was home to a racecourse of regional importance, linked to the estate at nearby Wentworth; the racecourse later fell into disuse although traces of the original track can easily be found between Wath and Swinton and its memory is left in local street names. There also was a pottery at Newhill, close to deposits of clay, although this always lived under the shadow of the nearby Rockingham Pottery in Swinton. Around the turn of the 19th century the poet and newspaper editor James Montgomery, resident in Wath at that time, described it as "the Queen of villages". This rural character was to change rapidly in the 19th and 20th century with the development of the deep mining industry.
The town lies within the South Yorkshire Coalfield and high quality bituminous coal had been dug out of outcrops and near-surface seams in primitive bell pits for many hundreds of years. Several high-grade coal seams are close to the surface in this area of South Yorkshire, including the prolific Barnsley and Parkgate seams. The industrial revolution and consequent massive increase in demand for coal led to a rapid industrialisation of the area in the 19th and early 20th century. The population of the area swelled and the local infrastructure was developed for the coal industry. The local economy became overly reliant on this one single industry; this was to store up problems for the future.
The Dearne and Dove Canal, which was opened in stages from 1798 to 1804 to access the local collieries on the southern side of the Dearne Valley, passed through the town just to the north of the High Street on a large embankment and then turned north into the valley; this wide section was known locally as the 'Bay of Biscay'. The canal finally closed in 1961 after many years unused and in poor repair. Much of the line of the canal in the town has since been used for new roads, one called 'Biscay Way'.
By the 20th century, heavy industry was evident in the area with many large, busy collieries operating. Wath Main and Manvers Main were the two usually associated with Wath. After the Second World War the collieries clustered around Manvers were developed into a large colliery complex, coal preparation, coal products and coking plant, which were not only visible, but also detectable by nose from miles around.