Searching for relatives of William Collins who immigrated from Ireland in the 1830's. He settled in North Carolina USA.

It's hard to search without more info than just a name.  It might help to do dna testing, since your matches may help to narrow down the search area.

For now, I can provide something of a hint.  In his Surnames of Ireland, MacLysaght says that the name Collins in Ireland (if it's not from an English settler family) is "nearly always the anglicized form of Ó Coileáin (coileán, whelp) which is also [anglicized as] Cullane.  This sept [a "sub-tribe"] is of Co. Limerick."  He does also mention another sept, Ó Cuileáin, found further south in Cork, and a Mac Coileáin sept found in western Ulster, which are both also sometimes anglicized as Collins, but the implication is that they are much less numerous.   The famous Irish politician, Michael Collins, was from southern Cork, so he may have been from that Cork sept.