Highgarden
Highgarden was the seat of House Tyrell and the regional capital of the Reach. Located on the banks of the river Mander, Highgarden sits astride the Roseroad, a major thoroughfare linking Oldtown and King's Landing. Highgarden also forms the southern terminus of the Searoad, which leads to Lannisport. As King's Landing, Oldtown, and Lannisport are the first, second, and third largest cities in the realm, heavy trade and traffic across a large swath of southern Westeros ultimately passes through Highgarden.
The golden roses and green fields that surround Highgarden serves as the inspiration for the Tyrell sigil and heraldry.
In Tyrell possession since Aegon's Conquest, more than three centuries ago, Highgarden was captured and sacked by forces of House Lannister and House Tyrell's formerly loyal vassals House Tarly, with its resources plundered, in the name of Queen Cersei Lannister. With the death of Lady Olenna Tyrell, the castle's ownership is uncertain.