Castletown until the middle 19th Century was the residence of the Governor and capital of the Island. The move to Douglas started under Governor Piggot (1860/63) when he could not find any suitable property to rent as Lorn House, the residence of previous Governors since 1845, had been reclaimed by its owner. Under his direction various Government offices moved to Douglas, though the Keys continued to meet at Castletown until 1874 when Governor Loch finally moved all offices to Douglas.
Castletown was little influenced by the tourist industry - as an 1898 official guide put it
The most striking peculiarity of Castletown is its intense respectability - a characteristic which for long kept it back from joining in the modern industry of the Island, the Summer Season. It is now beginning to recognise its mistake, and is doing its utmost to fit itself to be a modern holiday resort of the better and quieter class. Its accommodation is good, its tariffs are moderate, and its surroundings are such as should make it a favourite resting-place with the better class of tourists.
Although Castletown acquired some popularity amongst the more 'respectable' visitors it did not see the building of many holiday establishments, those along College Green were used by King William's College to house boarders and staff. A 1920 guidebook has "It has now, except during the mid-day Douglas invasion, a somewhat forlorn appearance, but bears its supersession with becoming dignity"
The town is dominated by Castle Rushen dating in part from the 12th Century though the towers and curtain wall are 14th.
Castletown is in Malew Parish where most of the population were buried, a chapel of ease was however long established in the town.
T.E.Brown's well known description of the class structure of Castletown c.1840 was that there were as many social classes in Castletown as rings round a Portugal onion. This would appear to be borne out by Blanchard's comments (Adam's Watering Places) of 1851 - "Speaking relatively of the inhabitants, we should say that they are somewhat exclusive and aristocratic".
Castletown Heritage has was formed in 1997 to help preserve the very attractive features of the town.
D Corlett Castletown: A descriptive guide  - a short guide to the town in the form of a walking tour.
Castletown Heritage issued a similar guide, heavily based on this, in 1999.
P.G. Ralfe Some Notes on Old Castletown Proc IoMNH&ASoc. Vol III No. 3 pp208-217
T.M. Moore Some Social Aspects of Castletown In the Eighteenth And Nineteenth Centuries. Proc IoMNH&ASoc. Vol VII No. 4 pp686-705
J. Roscow "The Development of Sixteenth century Castletown" Proc IoMNH&AS vol X #4 p301/325 1998
J. Roscow "The Development of Castletown 1601 to 1703" Proc IoMNH&AS vol XI #1 p5/28 2000
D Winterbottom Profile of Castletown Ramsey: Lily Publications 2010 ISBN 978-1-899602-39-1
Jonathan Kewley East of Roscow: Some Preliminary Thoughts on the Development of Castletown east of the Silverburn The Antiquarian #4 pp8014 Autumn 2011
Eva Wilson Castletown A Miscellany Castletown Heritage Occasional Papers No 3  ISBN 978-0-9545413-3-0