Looking for Conrad from Northumberland County Pennsylvania

The Conrad Family Tree written by Ralph H. Conrad - 1928-29 stated Peter Conrad came from Germany and settled in Northumberland county Pennsylvanis in 17??
He died and is buried there. The rest of the family moved in the summer of 1837-38 to northern Indiania near where Millersburg now stands 20 miles east of Elkhart. Some people by the name of Long came with them.

From Indiana the family moved to Billings, Christian county Missouri.
They came in April, 1877.

I am trying to find where in Northumberland county the family lived and when Peter CONRAD came from Germany and if anyone came from Germany with Peter.

Any information would be helpful.

Charlotte Trager