Wiktionary
n. The location that is the centre of authority to govern; usually the capital city of an area.
Wikipedia
The seat of government is (as defined by Brewer's Politics) "the building, complex of buildings or the city from which a government exercises its authority".
The national government is usually located in the capital. In most countries, the capital and the seat of government are the same city; for example, Ankara is both the capital and seat of government of Turkey. London is additionally the capital city of both England and the United Kingdom, seating the UK's government.
The terms are not completely synonymous, as some countries' seat of government differs from the capital. The Netherlands, for example, has Amsterdam as its capital but The Hague is the seat of government.
Local and regional authorities usually have a seat ( administrative center) as well.
Usage examples of "seat of government".
And this innovation, so agreeable to his active mind, was countenanced by the patience of the times, and his long absence from the seat of government.
The Saracens disliked the air and situation of the place, and Omar was advised by his general to remove the seat of government to the western side of the Euphrates.
Wherever the seat of government is fixed, a considerable part of the public revenue will be expended by the prince himself, by his ministers, by the officers of justice, and by the domestics of the palace.
It only surprises me that they would be this bold right here, in this very room, across from the seat of government.
The Cabinet insisted that his presence was legally required at the seat of government.
This was victory indeed, for Scow was the capital bubble of North Saturn, the seat of government for the Union of Saturnine Republics.
Many embassies and consulates to the CWO and to A-Io also clustered in Rodarred, only an hour's ride from Nio Esseia and the national seat of government.
Sleet and Carabella and their troops went upward, toward the imperial halls of the inner sector to take possession of the seat of government.
The Conclave Arena, seat of government of all the Gubru race and clan.
It was not only peace that was made, the two nations were united into one State, the royal power was shared between them, and the seat of government for both nations was Rome.