City Hall The City of Thief River Falls, population 8,722, is located in Northwestern Minnesota in Pennington County, approxi ... mately 70 miles south of the Canadian border, where the Thief River flows into the Red Lake River. Not only does Thief River Falls serve as a regional center for its agricultural base, it has also developed and retained a commercial and industrial base that includes numerous manufacturing and distribution center jobs, while being surrounded by rivers, wildlife refuges and forests. How did Thief River Falls get its name? Thief River Falls Invites You To Grow With Us! Advance Thief River Whether you looking for business opportunities or looking for a place to call home. We are here to help you. Donations are being accepted to repair rust, paint, and build a canopy, with new iron fencing, over the Soo Line steam locomotive 1024 located next to City Hall. Read all about it and donate here! read more