Last name เพ็ญคำ (Penkham 
, Phenkham , เพ็ญคำ) , in the entire world, is a very rare cognomen. The surname เพ็ญคำ is characteristic of Thailand, where it is a very rare surname, and the United States, where it is an extremely rare surname. Much less frequently, เพ็ญคำ is the forename as well as the last name.