It is believed to be a fort in Florida that was built by the Spainyards in the 1500s. Now it is just ruins but can be visited in Florida.
I believe the oldest court house is King William County Courthouse which was built in 1725 in Virginia. I hope this answer helped you out. Anymore questions feel free to ask.
The Palace of the Governors.
The Palace of the Governors.
The pentagon
pentagon
It is in New Mexico. The building, called the Hall of Governors, is in the capital city of Santa Fe.
The pentagon.
There are many thousands of government buildings in the US. The seat of the Federal government is in Washington DC.
I don't know ask some one else
Fort Sumter
The US does not and never has had a new government name
The capitol building is the meeting place of the US Congress which is the legislative branch of the US government.
Appalachian Mountains (oldest in US)
pentagon