| [assume Great Britain unless specifed] | |
| First Survey - England & Wales | |  |  |
| Ordnance Surveyors’ Drawings | |
| purchased a Ramsden theodolite | |
| first one-inch map of Kent | |
| Old Series (1 inch to 1 mile) | |
| six inch to the mile valuation survey - Ireland | |  |
| Triangulation - Ireland | | |
| Thomas Drummond invented the limelight | |
| first survey parties northern counties - Ireland | | |
| new boundary department - Ireland | | |
| Baseline Measurement - Ireland | | |
| datum for County Dublin - Ireland | | |
| Primary Spirit Levelling - Ireland | | |
| GB to be surveyed at the six-inch scale | |
| County series mapping - Scotland (+) | |  |
| large scale town plans - Scotland (+) | | |
| County series mapping - England & Wales (+) | | | |
| District and Tourist maps | |
| the twenty-five inch survey | |
| New Series | |
| Revised New Series | |
| One-inch 2nd edition - Scotland (+) | | |
| Third edition | |
| Fourth Edition | |
| (World War One) | |
| Popular edition | |
| One-inch "Popular" edition - Scotland (+) | | |
| OS split into OSGB, OSNI and OSI | |
| Fifth Edition | |
| (2nd World War) | |
| War Revisions | |
| New Popular (Sixth) Edition | |
| One-Inch Seventh Series | |
| 25,000 Second Series (Pathfinder) | |
| New Datum: Malin Head, Co Donegal - Ireland | | |
| large-scale Aerial photography - Ireland | | |
| metrication programme | |
| 50k first series - sheets 102 to 204 | |
| 50k first series - sheets 1 to 101 | |
| 50k Second Series | |
| Landranger Series replaces 50k | |
| Landranger gets colour 'locale' photographs on cover | |
| Outdoor Leisure Second Series | |
| Explorer Maps | |
| [assume Great Britain unless specifed] | |
