Kingdom of the River and the Hills

The Kingdom of the River and the Hills was one of the independent kingdoms of Westeros ruled by the First Men until the Andal Invasion. It was established on the modern Riverlands and took its name from the river Trident.

In the books
In the A Song of Ice and Fire novels the Kingdom of the River and the Hills was one of the many kingdomes established by the First Men, though at some point it extended over much of the Riverlands. It was ruled by House Mudd from their castle in what is known as Oldstones.

House Mudd was the last First Men dynasty to rule over the Trident. At some point during the Andal invasion, the Kingdom fell either to the Storm King or the ironborn.