Greetings!
The oldest Marr I have; William Marr, 13 Mar 1732; in Amwell, Hunterdon, New Jersey, USA . There is a Marr Story on Ancestry regarding a land disput story back to Scotland that I imagine you may have seen but just in case I mention it for you possible interest. Later Marrs, ended up in the Welland, Ontario area. I was quite surprise at all the Marrs; when I started to put that surname into search engines. Who would have guessed. Good Luck!