Please explain counties in England

Ahh, the difference between the City of London, and the city of London. One’s inside the other - ‘The City’ (as it is often referred) is the historical centre, now the financial district. ‘London’ generally refers to Greater London, of which the City of London is one small part (along with the City of Westminster, and thirty-something other boroughs). The London Assembly governs Greater London.

There’s also Maine, which was a part of Massachusetts until it was admitted to the Union as a separate state.

Nevada, before statehood, was part of Utah.

Plus, there was a “war” as to where the border of Michigan and Ohio would be. It ended up further north than Michiganers wanted, but then they got the Upper Peninsula.