The village of Mynydd Isa is located in between Mold and Buckley, Flinthsire. On the first edition of the 25inch OS maps, published in 1884, Mynydd Isa does not exist at all. On what is now the southern outskirts of the village there is a small settlement known as Pant-y-Fawnog which is served by a Calvinistic Methodist chapel (NPRN 8208) and the Griffin Inn. About half a mile to the north is an even smaller settlement or collection of farms known as Bryn y Baal. On the second edition of the 25inch OS maps, published in 1889, Bryn y Baal was spelled 'Bryn y B?l' and some workers housing seemed to have been built on the western edge of the settlement. Pant-y-Fawnog had grown slightly, and had a mission hall in addition to the Methodist chapel. It is not until the third edition of the 25inch OS maps, published in 1912, that the name 'Mynydd-Isa' appears, and it describes the area known as Pant-y-Fawnog in the previous maps. The village has expanded westwards and eastwards fairly substantially, and the Mission Hall has been renamed St. Cecilia's Church.
The village expanded rapidly during the twentieth century, and modern editions of the OS map show that housing has infilled the gap between what were once the separate settlements of Bryn y B?l and Pant-y-Fawnog. The Griffith Inn and St. Cecilia's church remain open, but the Methodist chapel had been demolished by 2009. The village has two schools. Ysgol Mynydd Isa, which 'opened in 2011 following the amalgamation of Mynydd Isa Junior and Wat's Dyke Infant schools' educates approximately 530 pupils aged three to eleven. Argoed High School educates approximately 600 pupils aged eleven to sixteen. Mynydd Isa's other amenities include a supermarket, a sports ground and a community run cafe and book club.
Sources: modern and historic OS maps; google maps; www.flintshire.gov.uk; Estyn reports on Ysgol Mynydd Isa, published in January 2013, and on Argoed High School, published in January 2016
M. Ryder, RCAHMW, 21st February 2019