I thought I would zero in on brothers Patrick and James since I have their death certificates so I am sure they were brothers because I have their parents names from the death certificates. I also found records for both of them on Family Search's Ireland Births and Baptisms, 1620-1881". they also had their parents listed and all matched up.
citations for these are: Ancestry.com death certificates, 1906-1963, No. 1055 (stamped) James Niland entry, died 13 Jan 1934, (digital image ancestry.com: accessed 17 Aug 2014) citing Pennsylvania (State) Death Certificates 1906-1963 Series 11.90(1,905 cartons), Records of the Pennsylvania Department of Health Record Group 11. Pennsylvania Historical and Museum Commission Harrisburg, Pennsylvania. Ancestry.com death certificates, 1906-1963, No. 52523 (stamped) Patrick Niland entry, died 10 May 1929, (digital image ancestry.com: accessed 17 Aug 2014) citing Pennsylvania (State) Death Certificates 1906-1963 Series 11.90 (1,905 cartons), Records of the Pennsylvania Department of Health Record Group 11. Pennsylvania Historical and Museum Commission Harrisburg, Pennsylvania.
Well the first record I found was a Passenger list leaving the UK from 1912. This was Patrick, his wife Margaret and their daughter, Sarah coming home from a visit to Ireland. So this tells me that I am going to have to look for passports for them very soon.
Then I found a Passenger list leaving the UK from 1890. This was Patrick and James coming to the US. If only the passenger lists back then gave the information that we get on the later ones.
citation: "Passenger List," digital images, (findmypast.com, accessed, 7 Mar 2015), manifest, British Prince, 3 July 1890, ticket no. 4571, Pat Niland, age 18 and Jas Niland, age 16
So I went looking for information on the parents. I found what I think are their death records. Sarah Niland died in 1878, the registration district is Swineford, Mayo, Ireland. Patrick Niland died in 1913, also Swineherd, Mayo, Ireland is the registration district. So I went looking for a marriage record for Patrick and Sarah. The death certificates had Sarah's maiden name as Coffield so that was what I was looking for, nothing came back! Then I looked again at Patrick and James' passenger list. the next on the list was a John Cahill but then there were two young girls with the last name of Caulfield and I wondered if this was the correct way to spell Sarah's name, possibly these two were family traveling together. Well that did the trick! In 1864 in the registration district of Swineherd, Sarah Caulfield married one of 4 men listed and one of them was Pat Niland! So there are more records to see if I can get. After I found this I looked again at the Birth and Baptism records for Patrick and James and saw that Sarah Caulfield was the spelling on them. And getting back to those records, the birth and baptisms took place in Kilkelly, Mayo, Ireland
So for the last piece of this I went looking for Austin Michael Niland. I do not have proof that he was another brother, but Patrick along with my great grandfather, James McCarry, were Austin's witness on his 1922 naturalization petition. On his petition and his passenger list, he said that he was born in Ballyhaunis, Mayo, Ireland. He said his last residence was Aghamore, Mayo and his father, Patrick is there. So I looked up his birth record and found him born in 1892 the registration district was Swineford.
citation: Point of entry record, ship: Merion, 17 Apr 1910, No. 453, Austin Niland, age 17.
So I went on Google Maps, found Kilkelly, to the northwest is Swineford, to the southeast is Ballyhaunis and Aghamore is halfway between Kilkelly and Ballyhaunis. So they all line up and to top it off, a little south west of Kilkelly is the town of Knock and my sister and I were in Knock when we were in Ireland in 2004. I knew nothing of the Nilands at that time, but we were so close to where they were, maybe some still there!
So my thoughts on the connection are this, the death record for Patrick Niland, Sr. has his birth in 1833. that would put him around the same age as my 2nd great grandfather, John Welsh. He was born in 1835, that could make them 1st cousins, so I am thinking John's mother, Catherine and Patrick's father were brother and sister. So now I have to see if I can find those Irish records and prove it!