1792 First Nantgwyn Chapel built
1801 Population of the parish 661
1807 St Harmon Wesleyan Chapel built
1821 St Garmon Church demolished and rebuilt
1825 Sychnant Chapel built
1839 St Harmon Tithe Map Apportionment, 103 landowners (about 50% owned less than 10 acres and about 50% of acreage owned by absentee landlords)
1839 Chartists riots in Llanidloes
1841 Census: 3 tailors, 3 carpenters, 2 blacksmiths, 2 masons, 2 shoemakers, 2 millers, 2 shopkeepers, 1 Baptist Minister. Remaining 150 households were farmers or labourers
1843 Rebecca Riots, Rhayader toll gates destroyed
1851 Populationof the parish 855 (increase of 194 since 1801)
1851 Religious Census: average attendance St Garmon 410, Sychnant 140, Nantgwyn 340
1852 Last of the St Harmon horse races at Baileyhaulwen (some disorderly scenes put an end to the event)
1857 Enclosure of much of the common land in St Harmon by the Manor of Gollon Enclosure Act. (additional land was enclosed by further Acts between 1843 and 1871)
1864 Opening of Pant y dwr Station on the Mid Wales Railway
1865 Turbary Charity Field donated to the parish by the Lord of the Manor of Clas Garmon
1873 Services in English began at St Garmon church (but Welsh services In the non-conformist chapels continued until 1870)
1873 National School, St Harmon opened
1874 Nantgwyn School opened
1876 Francis Culvert became vicar of St Garmon Church for a period of two years
1877 Second Nantgwyn Chapel opened
1879 St Harmon railway station opened
1894 First Parish Meeting and elections to the council (held at the National School, St Harmon)
1899 Maggie Rowlands of St Harmon was killed and six people injured in the Tylwch rail crash
1901 Population of the parish 653 (a decline of 201 since 1851)
1906 The first village hall built by public subscription
1908 New school at Nantgwyn opened
1908 St Garmon Church renovated
1913 Daily delivery of post office mail began
1914-1918 Nine local men lost their lives in the Great War
1929 Sychnant Chapel renovated
1941 Luftwaffe dropped bombs on Garn Hill (a patch of mist was mistaken for an Elan Valley reservoir)
1952 Mains Water supply provided
1954 Electricity supply provided
1955 St Harmon Women’s Institute formed
1959 National School, St Harmon closed
1962 Mid Wales Railway closed
1964 Minyfford development built
1964 Sewerage system built at Pant y dwr
1970 Proposed dam at Tylwch rejected by the government
1974 Telephone exchange built at Pant y dwr
1981 Nantgwyn School closed
1982 St Harmon parish gained additional land on the western slopes of Moel Hywel (recommendationof the Local Government Boundary Commission)
1987 Gilfach bought by the Radnorshire Wildlife Trust
1993 Tornado damages four farms and six sheep killed
1994 BrynTitli Wind Farm built
1994 Dolybont and Sun Hill developments built
2000 St Harmon football team formed
2010 Final Pant y dwr Eisteddfod
2011 Population 593 (a decline of 60 since 1901)
2012 Old hall demolished and new Community Hall opened
2017 Fiber optics laid and available to majority of community

(Much of the information above comes from St Harmon Council minutes and A Glimpse of Beautiful Mid Wales by local author Monty Williams)

A collision occurred early yesterday morning on the Cambrian Railway, at Tylwch station near Llanidloes, Montgomeryshire. It appears that an excursion train from Brecon to Belle View, Manchester, ran into the down mail which was standing in the station at the time. Two coaches of the excursion train were telescoped, and a girl, the daughter of a platelayer,was killed. Six other persons were injured, two seriously………..The drivers and firemen escaped with slight injuries, but one young woman, Miss Maggie Rowlands of St Harmon, a passengerby the excursion train, was killed on the spot. In addition six other passengers sustained more or less serious injuries, the worst case being that of a young man who had both legs broken……….. The injured were placed in the waiting-room, and medical assistance was requisitioned fromLlanidloes. Breakdown gangs arrived from Oswestry and Builth, and after a delay of some hours, both trains were able to proceed to their destinations, and by noon the line was again cleared for traffic.
(The Times, 17 September 1899)

Mr Evan W. Jones, J.P., of the Stores, Pantydwr, fished the Marteg stream on Thursday evening, and, during the short period of two and a half hours, caught no less than 102 fish.
(Brecon and RadnorExpress, 12 August 1915)

The Rhayader Fur and Feather Association furnish the following numbers of eggs received at the following depots during the past four weeks ending 3rd March, and which have been dispatched to headquarters weekly: Rhayader, 890; Bwlchsarnau, 189;St. Harmons, 171; Newbridge-on-Wye, 120: Pantydwr, 97; Llanwrthwl, 89; Argoed Mill, 84; Nantmel, 50; Elan Village, 50; and Ysfa, 20; total, 1760 A pleasing feature of this collection is the interest taken by the school children, and the number who have brought an egg a piece each week to their schools. The Rhayader chief depot receives strong support from generous Cwmdauddwr and the surrounding district.Bwlchsarnau holds pride of place among the sub-depots, though closely followed by St. Harmons. The lists of donors are too great for publication, but the monthly lists will be looked forward to with great interest.
(Brecon and Radnor Express 11 March 1915)

Rhayader and Llanidloes railway was completely blocked for the second time within twelve hours, when a train was stranded in a snowdrift after leaving St Harmon Station at seven o’clock on Wednesday evening.
A relief engine sent from Llanidloes was itself buried in a snowdrift by 9.15 p.m.  A further engine was despatched but before reaching the stranded train became stuck in another snowdrift near Pantydwr Station.  The three engines and the train with its 20 passengers remained snowbound all night and not until 8.20 a.m. on Thursday was the release of the first engine possible.  Shortly after mid-day the train was freed and able to proceed on its way…..
(Brecon and Radnor Express, 13 March 1947)