The Manapa-Tarhunta letter (CTH 191; KUB 19.5 + KBo 19.79) is a fragmentary text in the Hittite language from the 13th century BC.
Although this interpretation remains a viable hypothesis, it is not favored by current scholarship since the section divider seems to suggest that Piyamaradu's activities were a separate topic from the attack on Wilusa.
From other texts, scholars have generally concluded that the modern day Karabel Pass served as the southern border of the Seha River Land.
Since the Manapa-Tarhunta letter suggests that the kingdom included Lazpa, this would place its northern border in the area of the Troad.
In particular, Max Gander has argued that the text need not be read as suggesting that Seha ruled over Lazpa, and that it could have been located as far south as the Meander River.