The Llanidloes and Newtown Railway (L&NR) was a railway company between Llanidloes and Newtown in Montgomeryshire, Wales. It was promoted locally when plans for trunk railways passing through the locality were cancelled; local people saw that a railway connection was essential to the flannel industry in the district. The 17-mile (27 km) line opened in 1859, and at first was isolated from any other railway, but from 1861 it became connected to Oswestry by an allied railway company, and other companies also connected to it. From 1864 the company was incorporated into the new Cambrian Railways company.

Llanidloes is a town and community on the A470 and B4518 roads in Powys, within the historic county boundaries of Montgomeryshire, Wales. The population in 2011 was 2,929, of whom 15% could speak Welsh. It is the third largest settlement in Montgomeryshire, after Newtown and Welshpool.