Leitrim-Roscommon

Hi, in need of help from any experts out there.
I have an Ellen Nichol, born Mohill District, Leitrim, around 1881. She had sisters Bridget and Rose, and a brother James. Bridget, Rose and James all went to U.S.A, 1904, 1906 and 1909 respectively. All said they would stay with their sister Ellen. Bridget just said "sister Ellen", the other two said "Ellen Gray" and gave addresses. I've found a possible emigration record for Ellen in 1904, but it's not conclusive, but I think she probably married Gray in the U.S. But I've searched Ancestry for all variations and nearby addresses for 1910 and 1920 and can find nothing to match. Could anyone suggest how to go forward from here. All help appreciated.

Tom

Thanks Ed, that is very useful indeed. Ellen's father should have been Richard but Mary Doyle was her mother's name, so it sounds very promising. Also, thanks for putting me onto the LDS - for some reason I just assumed that anything 20th Century would not be on it.

Many thanks.

Tom