Television numbers say the exact opposite and that they are very close in terms of popularity throughout the country. The CFL generally averages better numbers through each of their regular seasons, but the NFL generally has the edge when it comes to the playoffs. Including the Super Bowl which outdraws the Grey Cup (usually in the 6 million range for SB, 4 million range for GC).
If you're looking at specific areas of the country then you will find a pretty big gap. e.g. If you're in southern Ontario the NFL holds a big edge as far as popularity goes there as the CFL is largely ignored when compared to the rest of the country. Conversely, if you're living in the prairie provinces then the CFL holds a substantial edge and is arguably more popular than the NHL in that part of the country.
Here's some television numbers from last fall comparing the two leagues. Source being BBM, which is Canada's official ratings provider;
Fri Oct 11: BC at Calgary — 659,000 TSN
Sat Oct 12: Edmonton at Saskatchewan — 778,000 TSN
Sun Oct 13: Packers at Ravens / Bengals at Bills / Steelers at Jets — 712,000 CTV (*CBS, Fox)
Sun Oct 13: Saints at Patriots / Cardinals at 49ers — 292,000 Sportsnet (*Fox, CBS)
Sun Oct 13: Redskins at Cowboys — 455,000 TSN (*NBC)
Mon Oct 14: Toronto at Hamilton — 956,000 TSN
Mon Oct 14: Winnipeg at Montreal — 686,000 TSN
Mon Oct 14: Colts at Chargers — 545,000 TSN
Fri Oct 18: Calgary at Edmonton — 631,000 TSN
Sat Oct 19: BC at Saskatchewan — 863,000 TSN
Sat Oct 19: Toronto at Winnipeg — 650,000 TSN
Sun Oct 20: Bills at Dolphins / Patriots at Jets / Cowboys at Eagles — 710,000 CTV (*CBS, Fox)
Sun Oct 20: Broncos at Colts — 725,000 TSN (*NBC)
Sun Oct 20: Hamilton at Montreal — 473,000 TSN
Sun Oct 20: Texans at Chiefs / Ravens at Steelers — 227,000 Sportsnet (*CBS)
Thu Oct 24: Winnipeg at Toronto — 517,000 TSN
Thu Oct 24: Panthers at Buccaneers — 105,000 Sportsnet 360
Fri Oct 25: Edmonton at BC — 604,000 TSN
Sat Oct 26: Saskatchewan at Calgary — 771,000 TSN
Sat Oct 26: Montreal at Hamilton — 451,000 TSN
Sun Oct 27: Dolphins at Patriots / Cowboys at Lions / Bills at Saints — 809,000 CTV (*Fox, CBS)
Sun Oct 27: Jets at Bengals / Redskins at Broncos 151,000 Sportsnet (*Fox)
Sun Oct 27: Packers at Vikings — 411,000 TSN (*NBC)
Thu Oct 31: Bengals at Dolphins — 448,300 Sportsnet
Fri Nov 1: BC at Calgary — 543,000 TSN
Fri Nov 2: Montreal at Toronto — 487,000 TSN
Sat Nov 2: Edmonton at Saskatchewan — 613,000 TSN
Sat Nov 2: Hamilton at Winnipeg — 437,000 TSN
Sun Nov 3: Chiefs at BIlls / Vikings at Cowboys / Saints at Jets — 555,000 CTV (*Fox, CBS)
Sun Nov 3: Steelers at Patriots — 497,00 City (*CBS)
Sun Nov 3: Colts at Texans — 408,000 TSN (*NBC)
