Hi, Laurie.Regrettably, since my Jacobs were in the 1600s and early 1700s, I haven't pursued any research on Jacobs who lived a hundred years later than that, as your Julia did.
The best place for guess work in genealogy is to guess where to research next.In that vein, I'd make these observations about Julia's parents Betsy Jacob and Aeneas Campbell :
1.In that era, single women were a little less mobile than men, so I'd guess that Julia was born in either DC or Prince Georges County, MD and that's the first place I'd look for her family.Of course, they could have been from anywhere.
2.For starters, imagine that Betsy Jacob was born about 1800 and Aeneas about 1795, making them 21 and 26 respectively when Julia was born.That helps guide your research, although if Julia was a youngest child her parents might have been born 20 years earlier, 1780 and 1775 respectively.But that tells you that the 1790 census would be a good place to look, and other documents around that time.
3.From your note it looks like you actually do have some additional information about Aeneas Campbell, as you mentioned Henrietta Chaney from Anne Arundel County as a wife, and Aeneas daugther (was she also Henrietta's daughter) Sintha, who married a Gaither.It would be important to organize all this information by families with a genealogical data base program like Family Tree Maker, so that you can provide all the information you have when making a query.It's frequent that information you may not think of is important is exactly what will help someone else make the link you want.
4.Jacob, Chaney, Gaither are all prominent colonial Maryland names.Take advantage of this site and post your queries in a new post on the three named family boards on Genforum.Put the name of the person you are seeking information about (Betsy Jacob, Henrietta Chaney, Sintha Gaither, respectively) in the subject line so that people browsing the list will spot it.Guess a date of birth for each and add it with a question mark -- it will be wrong, but it helps the reader know you want someone in the 1800's and not the 1600's.
Having posted the note, you'll never know when you'll get a response -- I've gotten responses to notes posted 5 years earlier, which are still available for reading.