Looking for the Relations of John and Jane Thompson Who Left Ireland Between 1802 and 1849 They Died IN Philadelphia PA

Both John and Jane and their son John were all born in Northern Ireland. They are buried in Mt. Moriah cemetery in Philadelphia PA. I believe they immigrated to Philadelphia after 1839. I have searched ships logs available on line but have not been able to piece together a logical story. Unfortunately for me, Thompson seem to be a common name in Ireland. Most probably they came to Philadelphia with other family members but I can't find any traces in the records. I don't know Janes's maiden name. They were Protestants here in America so were probably the same in Ireland. Later generations were of all different faiths.