Acadia (properly Acadie) was part of New France until 1763, when it became British territory. Most of what was Acadia is now in Canada, but it included parts of what is now Maine. More details at https://en.wikipedia.org/wiki/Acadia
Île Saint-Jean is now Prince Edward Island.
Port-Royal is now Annapolis Royal, Nova Scotia
Buckinghamshire (also abbreviated as "Bucks") is a county in England.
QC is an abbreviation for Québec, a province in Canada. (You may also see "PQ" for "Province of Quebec, although that's an old usage.)
NB is the abbreviation for New Brunswick, also a province in Canada (and once part of Acadia).
CT and Conn. are abbreviations for Connecticut, once a British Colony, now a state in the United States of America.
DC stands for District of Columbia (where Washington, the capital of the United States of America is located. It's a distinct territory, but doesn't have the same legal relationship to the rest of the country that states do. (To be honest, I don't understand the differences, but Americans hasten to point out that they're there.)
Glasgow is in Lanarkshire, a county in Scotland.
I'm guessing that Heiliges Römisches Reich is the Holy Roman Empire. https://en.wikipedia.org/wiki/Holy_Roman_Empire
Hertfordshire, also abbreviated as "Herts", is another county in England.
Liverpool is a city in England. Since 1974, it's been be part of the county of Merseyside. Prior to that, it was part of Lancashire (abbreviated as "Lancs".)
New York (also NY) was once a British Colony, and is now a state in the United States of America. Although "New York" may also refer to New York City. (But since the city is located within the state, the presence of either is a pretty good indication of at least the state level location.)
Northamptonshire (abbreviated "Northants") is a county in England.
Nouvelle France, without any more detail, could refer to Acadia, Québec, or Louisiana (not the current state, but the whole swath of territory from what is now Nova Scotia, Canada to New Orleans, Louisiana - although much of the land in between wasn't settled, just the occasional fur trading post before the British kicked the French out).
Rotterdam is a city in the Netherlands.
Upper Canada existed from 26 December 1791 to 10 February 1841 and generally comprised present-day Southern Ontario, Canada. From 1841 to 1867, it was known as Canada West. After 1867, it became Ontario, and eventually expanded to its present borders.
Virginia (also VA) was another British colony that became a state in the USA. During the U.S. Civil War, West Virginia (WV) was split off from Virginia.
Utrecht is a city in the Netherlands. It's located in a province, also named Utrecht.
Louisiana (abbreviated as "LA" without periods, not to be confused with "L.A." which is Los Angeles, California) was part of Nouvelle France, bought by the USA in 1810, and the territory of the French colony is now taken up by several states.