Istmina is a small city and municipality in the Chocó Department, Colombia.

The city of Istmina was founded in 1834 by Juan Nepomuceno Mosquera, initially with the name of San Pablo.

The name was changed in 1903 to Istmina, a contraction of isthmus and minas (mines), two characteristics of the area.

Istmina is located 75 km (47 mi) from the departmental capital, Quibdó.

Istmina has a very wet tropical rainforest climate (Af).