The city of Exeter is shown on most road maps as the county seat of Rockingham county, however, while on a trip there located the "new" courthouse in Brentwood. Is there a county courthouse in Exeter?

Is there a previous courthouse that is now used for other business?

What about the town hall--I have found mention that the town hall was built in 1855 as "town hall-courthouse", is this true?

In New Hampshire the term "county seat" means little more than the current location of the County Courthouse. In 1855 they shared the same building in downtown Exeter, and in 1893 a new one was built. That one was destroyed in 1969 and the courthouse moved to a new building in Exeter. It moved to Brentwood ten or so years ago when they again outgrew the old courthouse and had to build a new one.

Unless New Hampshire is very different from other states, the county seat is the place where its elected officers/supervisors meet to conduct the public business of the county. It's also the place where the offices of the county's paid administrators are located. In many, if not most states, a county many have more than one court house, but it will have only one building where it conducts its public meetings and where the offices of the County Clerk and the Chief Administrator are located.

Now, records keeping/storing/archiving is a whole different ball game. These are usually the matters of genealogical focus.

teschek -- would you kindly message me? I have info regarding your Bordieri tree posted. Thanks!