LaBrunes

I don't know how to go back further in time with the LaBrunes.  I first found them in 1840 in Stonelick Township, Clermont co., Ohio.  Ten years later they were in Dubuque co., Iowa, where they settled.  By comparing the two censuses you can see that two children are no longer with the family in 1850: a son born between 1820 and 1830 in France and a daughter born between 1835 and 1840, we know not where.  I'm assuming the daughter passed away since she would only be 10 to 15 years old in 1850, so probably still living with the family.  The missing son, on the other hand, would be 20 to 30 years old and could easily have gone his own way.  Somewhere.  There are not many LaBrunes in the United States in the mid 1800s, which should make it easier to find any stray family members.  But I haven't found any.  A while back I found a LaBrune was married in Brown co., Ohio, adjacent to Clermont co. where our LaBrunes had lived, in 1868.  I was hoping that this might be the missing son, who had stayed in Ohio.  Recently, though I found some more information.  The 1868 marriage was between a Philip LaBrune born in about 1796 and  a Josephine Oligee born in about 1804.  Not what I was looking for.  But it is odd that a LaBrune would live so close to where our LaBrunes used to live.  And he has the same name.  And the same age.  So now I'm considering this: Our last record of Philip in Dubuque was on an 1865 property tax list.  Ann, his wife, died in 1868 and is buried in Rickardsville, near Dubuque.  But Philip is not buried there.  I'm starting to think that after the death of Ann, Philip went back to Ohio - I'd like to find out why - and remarried.  I'm going to look into this more ....

Which is straying from my original point.  The LaBrunes came from France, since Philip, Ann, and some of the kids were born there.  They probably sailed to French-speaking Canada, then headed into the United States.  All of this travel took place between the birth of Nicholas in about 1831 and their presence in Ohio in 1840.  Where to look for records?