Just to give you a little impression to which area Ostfriesland belonged only during the lifetime of George Juetting:
When he was born, it belonged to the "King of Great Britain and Hanover" according to a paragraph of the treaty of the Congress of Vienna. In 1866 Prussia annexed Hannover, so it became de facto a Prussian province, which it de jure became in 1871, when Hanover became a Prussian province in the German Confederation (Deutscher Bund).
The German wikipedia article gave me another idea: Did you know there were issued in the USA the "Ostfriesische Nachrichten", a German written newspaper specifically for the Ostfriesen-immigrants in the USA? Maybe it's worth to have a look there if you find something.