The Roud Index does have lots of North American entries. To restrict your searches to these, fill out what you want to search for, then click on '+ Add More Fields' and enter in the field text '(USA or Canada)' and chose in the field within 'Country'.

Unfortunately I don't have such options on Mainly Norfolk. And it grew out of a fan page for a few 1970s English folk rock group and concentrates on English and Scottish albums with a spattering of Irish, America