My friend John Kafentzis passed along a list.
"Both have AFBs, small Catholic colleges and are the medical center for their region.
"Both used to have a major heavy manufacturer, Kaiser in Spokane, Anaconda in Great Falls.
"Both are farming hubs.
"Both have modest ski hills nearby that someone always has expansive dreams for.
"Both have disproportionate interest in figure skating and hockey.
"It is still major news in both places when a commercial air route is added.
"Feelings of civic inferiority periodically wash over both.
"Both are touted as great places to raise kids but not necessarily called that by kids.
"Spokane had Bing Crosby, Great Falls had Charlie Russell -- both legends in their areas of artistic endeavor. (It is curious that nobody named a school around here after Bing.)
"Oh yeah, and both have breathtaking waterfalls."