Modern ĭuring the 14th century, Lynn ranked as England's most important port. Lynn's 12th-century Jewish community was exterminated in the widespread massacres of 1189. Trade built up along the waterways that stretched inland the town expanded between the two rivers. He commissioned St Margaret's Church and authorised a market to be held on Saturday. In 1101, Bishop Herbert de Losinga of Thetford began to build the first medieval town between the rivers Purfleet to the north and Mill Fleet to the south. After its redirection, Lynn and its port gained significance and prosperity. Until the early 13th century, the Great Ouse emptied via the Wellstream at Wisbech. Development began in the early 10th century, but the place was not recorded until the early 11th century. Lynn originated on a constricted site south of where the River Great Ouse now discharges into the Wash. The city of Lynn, Massachusetts, north of Boston, was named in 1637 in honour of its first official minister of religion, Reverend Samuel Whiting (Senior), who arrived there from Lynn, Norfolk. The town is generally known locally as Lynn. Domesday records it as Lun and Lenn, and ascribes it to the Bishop of Elmham and the Archbishop of Canterbury. The town was named Len Episcopi (Bishop's Lynn) while under the temporal and spiritual jurisdiction of the Bishop of Norwich, but in the reign of Henry VIII it was surrendered to the crown and took the name Lenne Regis or King's Lynn. The presence of salt, which was relatively rare and expensive in the early medieval period, may have added to the interest of Herbert de Losinga and other prominent Normans in the modest parish. As the 1085 Domesday Book mentions saltings at Lena (Lynn), an area of partitioned pools may have existed there at the time.

The name Lynn may signify a body of water near the town – the Welsh word llyn means a lake but the name is plausibly of Anglo-Saxon origin, from lean meaning a tenure in fee or farm. The etymology of King's Lynn is uncertain.

King of the railway