Trallungelloyn, -golleyn, Trallunggolloyn 1310, Tralleong y gollen c.1560, Trallongolloyn 1577, Trallwyn-gollwyn 1597-8, 1617-18, Trellungollen 1636, Trallwng Gollen 1637, trallwyn gollwyn 1647, Trallomgollen 1761.

[The aerial photograph shows the main road running west-east in the town made up by Mount Street. High Street, Broad Street and Severn Street. This is the core of the medieval borough of Welshpool alias Pool/Y Trallwng. The boundaries of the original borough established in the 13th century corresponded with those of a small township known as Pool Town. Trallwng Gollen referred to a township which lies to the right(south) of this view around Powis Castle. The name is no longer current but extended to Severn Street and included part of Berriew Street.]

Part of the parish of Welshpool centred on Powis Castle/Castell Coch extending to Severn Street and Berriew Street in the town. Welshpool: Welsh tallwng, bog, muddy pool' and a personal name Collwyn or Gollwyn. Later spellings show association with collen, 'hazel-trees'. The qualifier distinguishes Trallwng Gollen from Trallwng Llywelyn which was the name of a township on the north side of the town containing the personal name Llywelyn. Trallwyng Llywelyn otherwise known as Welshtown and Tregymraeg once possessed its own chapel Capel Llywelyn.