Ysgol Bro Plenydd, a Welsh medium primary school, is located in the rural village of Y Ffor / Four Crosses, north of Pwllheli. The school was built in 1912 as Four Crosses Council School and appears on OS 25-inch 1917 Edition Sheet XXXIII.13 (surveyed 1887, revised 1914). The school was designed by architect to the Education Committee, Rowland Lloyd Jones on open air princiles. Along with Ysgol Brynaerau (NPRN 801310), the school at Four Crosses was a pioneering model for open air schools in Wales, with Jones and Caernarfonshire Education Committee displaying awareness of contemporary ideas surrounding school design, drawing on examples in Germany and demonstrating a progressive approach to school design that brought public health matters into the realms of education.

The school is adjacent to Ysgol Hafod Lon (NPRN: 417533).

Photographed during aerial reconnaissance by RCAHMW on 13th June 2008.
L. Osborne, 7th September 2012. Updated by M. Powel, RCAHMW. February 2025.

Sources: OS Map 25-inch 1917 Edition Sheet XXXIII.13; school website; 'New Open Air School at Four Crosses', Merioneth News and Herald and Barmouth Record, 4 October 1912, p.2.