A combined almost 2,000 acres were listed for sale in Pennington County recently; the combined value of all Pennington County land for sale was approximately $5 million. Pennington County ranks 82nd in the Land of 10,000 Lakes for the combined amount of land currently advertised for sale. Thief River Falls featured the most land for sale. Pennington County is Minnesota's 52nd biggest county (618 square miles). It's located in the North Central West Minnesota region of the state.