Control of Skrælige at the start of the war, 1775. Red indicates areas under firm British military control, blue indicates areas under control of the Massachusetts Provisional Congress (i.e. the rebels), pink indicates mixed control.
The Battles of Lexington and Concord led to the retreat of British forces to Charlestown, and the colonial forces put Boston under siege. In Skrælige, the British controlled the lower Siguan River Valley due to their presence in Fort Charles. Many in Skrælige sympathized with the rebels, especially the English-speaking settlers from New England who settled in the outer settlements. Sentiments weren't quite as strong in the lower Siguan Valley though, where a substantial part of the population was still Skræligen-speaking, and the ideas of the "rights of Englishmen" didn't take hold over people who weren't really English in quite the same way.
That sympathy began to wane rather quickly, however. Later in 1775 American privateers raided Littlevik (the only outlying town not sympathetic to the rebels) and attacked shipping routes to Skrælige. This led to a partial blockade of the islands that would last for the next three years.
The war was not going well for the British regulars on the mainland. Governor Thomas Gage was recalled without a replacement on the 11th of October, and then Boston was evacuated on the 17th of March, 1776. This left Skrælige without its formal government present. Lieutenant Governor of Nova Scotia and Naval Commander Mariot Arbuthnot effectively took charge at this point (Governor Francis Legge had also been recalled), though the Þing began to assert local control in non-military matters. By the end of 1778, all of Skrælige was back under the control of the British.
1779 began a new strategy for the British: settling a new colony in Penobscot Bay, Maine for Loyalists, called New Ireland. This would also make Skrælige less isolated from the remaining British territory - at this point, British control to the south was limited to New York City (after recapturing it in July 1776) and coastal Georgia around Savannah (after its capture in December 1778), so a colony between Skrælige and Nova Scotia would strengthen supply lines. So on the 30th of May, eight British navy ships set sail from Halifax with 640 troops. They captured the village of Castine and erected Fort George up the hill. The Commonwealth of Massachusetts launched an expedition to retake the area, and laid siege to Fort George for 21 days. Despite outnumbering the British, the Massachusetts forces had to retreat upon the arrival of reinforcements, and then burn their ships when they were blocked in Penobscot Bay. After such a significant victory, the colony would not be invaded again for the remainder of the war.
The war effectively came to and end in October 1781 with the British army surrender at Yorktown, Virginia. The rescue fleet sent for the British, who were already in retreat, were intercepted by a larger French fleet. Without a way out, the army was forced to surrender. New York City, Charleston, and Savannah were still occupied by the British, as well as New Ireland and Skrælige, but the British made no further attempts to invade.
Peace negotiations began in Paris in April, 1782. The first proposal from the French would set the western border of the United States at the Appalachians. This was strongly opposed by the Americans, as one of the acts that helped spark the conflict in the first place was the Proclamation Line of 1763, which bounded settlement to the eastern Continental Divide. Ultimately this led to the United States to negotiate directly with the British for a better deal.
The questions of New Ireland and Skrælige had to be dealt with as well - both were claimed by Massachusetts, but occupied by the British. The British were usually generous to the Americans in the treaty, with the hopes that the US would be a valuable trade partner in the future. (This would in fact be the case.) For this reason, New Ireland was granted back to the US, and its residents moved west to found St. Andrews in what became New Brunswick. Skrælige was tricky though. On the one hand, it was a British fortification very close to New Hampshire and Massachusetts (including Maine), but the divided population meant that it would potentially be a rebellious area to try to administer. Given the challenge this might face for the new country, the US accepted the cession of Skrælige. This was made easier by the very generous terms elsewhere, which drew the western border of the US at the Mississippi River.
The first initial impact of the loss in the Revolutionary War was migration. Tens of thousands of Loyalists fled the 13 newly independent states, including about 35,000 to Nova Scotia (which effectively included Skrælige by this point), 2,000 to Prince Edward Island, and 10,000 to Quebec (which also included modern day Ontario). Smaller numbers fled further, bound for Britain itself or the British West Indies.
Of the 35,000 the fled to Nova Scotia, 4,000 moved to the islands of Skrælige. Of these, around half accepted land grants in the upper Siguan River Valley in the towns of Egilstead and Bradstreet. There was some conflict with the new Loyalist immigrants, as a substantial proportion of the citizens outside of the lower Siguan River Valley were colonists from New England. However, given the vast numbers of new immigrants, the New Englanders were forced to either leave or accept the new citizens. The population of the lower valley was more mixed between Skræligen-speakers, English-speakers, and others, and the impact of new immigration was less significant. The earlier Þorormur Plan in Skrælingborough and the Havant Grid plan made housing the immigrants a much more straight-forward process.
Another significant demographic to move to Skrælige were black people, both free and enslaved. Prior to 1780, there were approximately 150-200 black people on the islands, most of whom (but not all) were slaves. In the following decade this population more than doubled due to two factors: Black Loyalists, and the slaves of White Loyalists. The British crown had promised freedom to slaves who could escape and serve the Loyalists, starting with Dunmore's Proclamation in November 1775 in Virginia. This was expanded by the Philipsburg Proclamation on the 30th of June, 1779, to free escaped slaves (from Patriots) in all of the colonies. Thousands of slaves escaped, so many that some slaves were ordered to return to their masters. The British did not regularly keep their promise to free escaped slaves, sometimes selling them back into slavery, but did ultimately facilitate the emigration of several thousand. This included around 3000 who were evacuated from New York to Nova Scotia, of which 300 ended up in Skrælige.
The White Loyalists, however, brought some slaves of their own, roughly 80 of them. This meant that now free black people outnumbered slaves, which helped rejuvenate the abolition movement in Skrælige. The new Massachusetts constitution banned slavery*, but of course this only applied to the American-controlled portion of the province. The legal status of slavery in Skrælige was unclear - once it was merged into Nova Scotia (see below), there was no longer any legal backing for the practice. A combination of abolitionist movements and the diminishing economic benefits of slavery meant that the practice died out in the early 19th century, well before the formal abolition across the British Empire in 1834.
*This is an oversimplification. Slavery was not formally abolished, but a series of cases before the Massachusetts Supreme Judicial Court in 1781 established that slavery was against the new state constitution (effective 1780). This did not immediately free all slaves, but did remove any legal support, and the number of slaves in Massachusetts was recorded as 0 in the 1790 census.Skrælige had been a part of the Province of Massachusetts Bay, but the rest of the province was in rebellion against Britain. Until the signing of Treaty of Paris in 1783, Skrælige (when under control of the British) was governed from Halifax, Nova Scotia, and the treaty then formalised this by merging Skrælige into Nova Scotia. In the summer of the next year, however, the influx of Loyalist immigrants led to the division of Nova Scotia into four separate parts. The continental portion of Nova Scotia was split into New Brunswick as a primarily Loyalist colony. Cape Breton was also split off, although it rejoined Nova Scotia in 1820. Finally, Skrælige was now an independent colony, the Province of the Skrælig Islands.
The Þing took this opportunity to reorganize and become the formal legislature of the province. Governor Thomas Spencer was appointed by the British Crown, although he was demoted to Lieutenant Governor in 1786 when the governorships of British North America were consolidated and Guy Carleton was appointed Governor General of the Canadas. The final reorganization took place in 1791, when Quebec was divided into Upper and Lower Canada in order to better separate the French-speaking Canadians from the new Loyalist immigrants.
The last census was completed in 1764, but further immigration, the wave of Loyalist refugees, and separation of the islands into their own colony, another count was needed.
The town-by-town results of the 1786 census were:
Abenakiborough: 719 (+470)
Copperstein: 297 (+88)
Havant: 1,691 (+1,220)
Middleton: 1,582 (+765)
Newhope: 1,724 (+527)
Main Town: 1,610 (+495)
Stefnabjarg: 114 (+32)
Northstead: 1,730 (+863)
Main Town:1,701 (+836)
Vitathorpe: 29 (+27)
Ragnarsson: 340 (+99)
Skrælingborough: 5,655 (+1,758)
Central Area: 5,179 (+1,532)
New Jorvik: 476 (+226)
Atlantica: 123 (+84)
Bradstreet: 1,234 (+1,118)
Burnet: 45
Egilstead: 1,501 (+1,184)
Fjallvik: 183 (+127)
Freydiston: 197 (+134)
Littlevik: 516 (+261)
Middlesun: 341 (+183)
Northbay: 171 (+100)
Northney: 238 (+146)
Northsound: 36
Raskrom: 702 (+398)
Southfall: 92 (+45)
Southreyn: 54 (+23)
Thorfall: 195 (+106)
Total: 19,366 (+9,780)
At a broader scale, there were three large demographic groups: Old Skræligens, Yankees, and Loyalists. Old Skræligens formerly referred to people descended from the independent Skræligens before Danish rule (as well as assimilated Abenaki), but with time came to include descendants of other Scandinavian immigrants. Depending on the definition used, this was about 5-6,000 people in the 1786 census. Yankees referred to English immigrants during its time as part of Massachusetts Bay. They were the largest group, at around 8,000 in the 1786 census. Many of these immigrants were from New England, and settled outside of the Lower Siguan Valley. These were the strongest supporters of being part of the United States. Loyalists were the latest group, which started with a minority of English immigrants but grew massively in the aftermath of the Revolution. By 1786 they numbered over 4,000. They were strong supporters of the Crown & the larger Empire. In addition, some prominent minorities included Jews (who were mostly separate from the other groups, numbering around 200), "Unassimilated Abenaki" (Abenaki who accepted Skræligen rule, but otherwise stayed separate, numbering around 400), and Black Skræligens (~550 of them). Black Skræligens were in no way a monolith though - some were current or former slaves, both of Yankees and Loyalists. A large new group though were the Black Loyalists - former slaves throughout the United States who escaped and fought for the Loyalists in exchange for the promise of freedom.
Based on the census, formal districts (nyr þingha, in reference to the original þingha) were drawn up for the Þing, apportioning a set number of representatives per district:
Skrælingborough (and Copperstein, which was subsequently annexed): 6 Þingmenn (MÞ)
Middleton & Abenakiborough: 2 Þingmenn
Havant: 2 Þingmenn
Newhope & Raskrom: 2 Þingmenn
Northstead & Ragnarsson: 2 Þingmenn
Bradstreet & Egilstead: 3 Þingmenn
Freydiston & Southern Islands: 1 Þingmaðr
Atlantic District (Littlevik, Thorfall, Atlantica): 1 Þingmaðr
North District (Northney, Burnet, Northbay, Northsound, Fjallvik): 1 Þingmaðr
This created a new Þing with 20 members, and rebalanced it to be mostly proportional to the current population.
For a more comprehensive look at the Black Loyalists, I recommend Episode 187 of the Lions Led by Donkeys podcast.
There are a couple of minor errors with the maps above concerning Prince Edward Island:
In the 1775-83 map, PEI is not labelled, despite it being a separate colony from Nova Scotia.
In the 1786 map, PEI is incorrectly labelled. The island and the corresponding colony was known as St. John's Island until 1799.
The population charts above are linked to a spreadsheet, and I forgot to open up permissions until September 16th - sorry about that!