Yes, the Crownlands are indeed directly controlled by the ruling king on the Iron Throne. Here’s a more detailed description:

The Crownlands
Capital: King's Landing
Ruling House: The ruling house varies depending on who holds the Iron Throne. Initially, it is House Targaryen, followed by House Baratheon, and later House Lannister and House Targaryen again in the TV series.
Geography: The Crownlands are located on the eastern coast of Westeros, surrounding Blackwater Bay. The region includes several key locations such as:
King's Landing: The capital of the Seven Kingdoms and the seat of the Iron Throne. It is the largest city in Westeros and the political heart of the realm.
Dragonstone: An ancient seat of House Targaryen, located on an island in Blackwater Bay. It serves as a strategic fortress and has a significant history with dragons.
Blackwater Bay: The bay that King's Landing overlooks, known for the crucial Battle of the Blackwater during the War of the Five Kings.
The Kingswood: A forested area south of King's Landing, known for its game and hunting grounds.
Political Significance
The Crownlands are central to the political power of the realm, as they contain King's Landing and the Iron Throne. The ruler of the Crownlands wields significant influence over the other regions of Westeros. Control of this area is vital for anyone aspiring to rule the Seven Kingdoms.

Would you like more details about a specific location or house within the Crownlands?