The Teifi Valley Railway was originally conceived as a 7 ft 1⁄4 in (2,140 mm) Brunel gauge line between Carmarthen and Cardigan. The line was opened temporarily in 1860, under the South Wales Railway and was fully opened the following year. It was operated by the Carmarthen and Cardigan Railway between Carmarthen and Cynwyl Elfed. In 1864, the line was extended to Pencader and Llandysul and, by 1872, had been converted to 4 ft 8 1⁄2 in (1,435 mm) standard gauge. By this time though, the line was bankrupt. Eventually the line was bought by the Great Western Railway which extended the terminus to Newcastle Emlyn. Passenger trains ceased to operate in 1952 and, in 1973 when freight services discontinued, the line was closed and dismantled. All that was left were platforms, bridges and a tunnel.
Although attempts had been made in 1973 to preserve the railway at standard gauge, it was not until 1981 that any true restoration project got under way. A group of enthusiasts bought the trackbed and, in 1983, laid a 2 ft (610 mm) gauge track. The line originally ran from Henllan to Pontprenshitw, where passengers were invited to take a short walk to see the waterfall under the railway bridge. In 1987, the line was extended as far as Llandyfriog and, in 2006, was extended to Pont Goch. From July 2009, the Henllan platform was relocated to the site of the original GWR site.
From this date, the Railway suffered a loss of trained personnel and operation for a full season became more and more difficult. In 2013 two directors resigned fearing that the Railway was facing closure. A local businessman took on the tenancy of the cafe and shortly after, operation of the whole business. Reports on the poor condition of the railway track, locos and rolling stock were ignored and eventually brought about the closure of railway operations. There were however no attempts to repair the track, but the tenant removed the first stretch of rail and began operation of a land train. Following an ORR inspection the Teifi Valley Railway suspended rail services in June 2014 and the Company was reprimanded for having passed rail operations to another operator.
From July 2014 the Teifi Valley Railway no longer operated as a railway; no trains ran and the track was removed from Henllan to Pontprenshitw, a tractor-hauled 'land train' providing rides on a short section of the trackbed. It was discovered in the autumn that the tenant had no intention of repairing or relaying the track, but rails had been removed so that commercial timber fellers could access the large spruce plantation just past Pontprenshitw. The track beyond Pontprenshitw had not been taken up and was severely damaged. The tenant left the scene and declared himself bankrupt. In November 2014 a new group took over management of the Railway and funds were sought to relay some track and resume operations in 2015. As of May 2016, track relaying has reached as far as Forest Halt, and train operations have resumed.