Mercia (Kó͘ Eng-gí: Miercna rīce) sī Anglo-Saxon Chhit-ông-kok (Heptarchy) sî-kî ê ông-kok chi it. Pún ông-kok ê tiong-sim tī Trent Hô iân-hōaⁿ, ia̍h tio̍h sī kin-á-ji̍t kóng Tiong-pō͘ Eng-lân.