The specific name refers to the native Taiwanese Ketagalan people inhabiting the area.

[4] Orobdella ketagalan has firm, muscular, and elongated body that gains streadily in width in the caudal direction.

The body is dorso-ventral depressed, with the sides nearly parallel from mid-length to the point just anterior to the caudal sucker.

[1] Leeches of the genus Orobdella are terrestrial, inhabit the banks of mountain streams, and feed on earthworms.

The type series of Orobdella ketagalan was collected at elevations of 600–779 m (1,969–2,556 ft) above sea level.