In the United States, most people are aware that radio and TV stations in the West usually begin with a K and those in the East usually begin with a W.
The Mississippi River is the dividing line everywhere except northern Minnesota, running right through a number of Upper Midwest markets. In many of those border markets, the FCC has allowed stations starting with a K east of the Mississippi and stations starting with a W west of the Mississippi.
From a historical standpoint, an article on the U.S. Early Radio History website explains that the dividing line was originally farther west, leading to a few legacy “W” callsigns now west of the Mississippi. The article explains that a few other “W” callsigns in Iowa were requested shortly after the line was moved. But the reason that a few “K” callsigns ended up in Wisconsin, far from the border, is a mystery.
It gets even murkier in Minnesota for reasons we’ll get to below. Excluding those pesky Minnesota stations, here’s a list of Upper Midwest stations that defy the K/W convention:
| Station | Possible reason | |
| KBJR-TV Superior, WI | Border market | |
| KDKE Superior, WI | Border market | |
| KFIZ Fond du Lac, WI | Unknown (granted 1923) | |
| KQCJ Cambridge, IL | Border market | |
| KSPP Rhinelander, WI | Unknown (granted 2012) | |
| KUUL East Moline, IL | Border market (originally used in Iowa) | |
| KUWS Superior, WI | Border market | |
| WCGD-LP Edgar, NE | Unknown (granted 2014) | |
| WDAY Fargo, ND | Historical | |
| WDAY-TV Fargo, ND | Derived from AM callsign | |
| WDAZ Devils Lake, ND | Derived from WDAY-TV | |
| WDBQ Dubuque, IA | Border market | |
| WHO Des Moines, IA | Historical/requested | |
| WHO-DT Des Moines, IA | Derived from AM callsign | |
| WJAG Norfolk, NE | Historical | |
| WJOD Asbury, IA | Border market (originally used in Illinois) | |
| WLLR Davenport, IA | Border market (originally used in Illinois) | |
| WMT Cedar Rapids, IA | Historical/requested | |
| WNAX Yankton, SD | Historical | |
| WNAX-FM Yankton, SD | Derived from AM callsign | |
| WOC Davenport, IA | Historical | |
| WOI Ames, IA | Historical | |
| WOI-FM Ames, IA | Derived from AM callsign | |
| WOI-DT Ames, IA | Derived from AM callsign | |
| WSUI Iowa City, IA | Historical/requested |
Meanwhile, Minnesota callsign rules are confusing for two reasons.
First, the Mississippi River runs through St. Paul, Minneapolis, St. Cloud, Little Falls, Brainerd, Grand Rapids, and Bemidji, so all of those cities are technically on both sides of the river. Excluding the river cities themselves, here are stations licensed to other communities near those cities that defy the K/W callsign division, apparently due to their presence in a border market:
- KBEK Mora
- KCIZ-LP Brunswick
- KLCI Elk River
- KMKL North Branch
- KQQL Anoka
- KTMY Coon Rapids
- WBKK Wilton
- WGVX Lakeville
- WWWI Baxter
- WWWI-FM Pillager
- WZFJ Breezy Point
Then there’s the confusing fact that the Mississippi River actually runs from west to east in northern Minnesota before it heads south. Instead of being west or east of the river, part of the state is north of it.
Though the Early Radio History article explains that there is supposedly a dividing line running from Lake Itasca to an unknown point east of International Falls, the actual record shows that there are 21 stations east of this line with “K” callsigns. Half of them are in the Duluth area, which is about 60 miles east of the Mississippi.
- KADU Hibbing
- KBAJ Deer River
- KBMX Proctor
- KBFT Nett Lake
- KCWV Duluth
- KDAL Duluth*
- KDAL-FM Duluth
- KDLH Duluth
- KDNI Duluth
- KDNW Duluth
- KKCB Duluth
- KKIN Aitkin
- KKIN-FM Aitkin
- KLDJ Duluth
- KQDS-FM Duluth
- KQDS-DT Duluth
- KRFG Nashwauk
- KTCO Duluth
- KTWH-LP Two Harbors
- KZIO Two Harbors
- KZJZ Babbitt
*In an interesting historical footnote, KDAL Duluth actually was originally licensed west of the Mississippi. The station’s official license traces to KGFK Hallock, which signed on in 1927. FCC history cards show it moved to Moorhead in 1930 and then to Duluth in 1936, the same year it changed its callsign to KDAL (despite being east of the Mississippi by that time).