One of those regional rivalries is BYU-Colorado State.

It’s been more than 15 years since the Cougars and Rams have met on the football field, but the two programs renew that rivalry on Saturday in Fort Collins, game No. 70 in a series that began in 1922.

Much has changed since the last meeting in 2010. BYU left the Mountain West Conference and navigated independence before joining the Big 12 in 2023.

Colorado State built a new stadium in 2017 at the cost of $220 million and has joined up with the rebuilt Pac-12. Hosting the Cougars will undoubtedly fill Canvas Stadium to capacity (41,200) and give the Rams a chance to earn a huge win in front of a national (CBS) television audience.

Colorado State won that first meeting in 1922 by a score of 33-0. Six of the first seven games were played in Fort Collins and the Rams won the first six before BYU earned a 20-12 victory at Provo in 1938.

The two teams met pretty much annually in several different conferences, but things got really interesting in the 2000s when both programs were in the Mountain West.

Colorado State won three of four from 2000 — the final season for legendary Cougar coach LaVell Edwards — to 2003. Luke Staley, who would go on to win the Doak Walker Award as the best running back in the country, scored four touchdowns in a 56-34 win at Provo in 2001.

That 2003 game was a 58-13 Rams win, with Bradlee Van Pelt throwing three touchdown passes and Marcus Houston adding three scores on the ground. It was the worst home loss for BYU since a 48-0 drubbing at the hands of Wyoming in 1950.

The Cougars then won the next seven meetings. That included several notable performances, including Max Hall twice throwing for 350-plus yards against the Rams, including once throwing a TD to Dennis Pitta with 22 seconds left for a 45-42 road win in 2008.

The final matchup saw Jake Heaps throw four touchdown passes to Luke Ashworth in a 49-10 win in 2010.

Then BYU went its separate way into independence.

There are several coaches on the Cougar staff — including head coach Kalani Sitake, offensive coordinator Aaron Roderick, defensive coordinator Kelly Poppinga and Harvey Unga, now the team’s running backs coach — who played pretty much annually against the Rams in their playing days at BYU.

(Colorado State nickels coach Matty Ah You was a linebacker for BYU in those Mountain West days, too.)

“I remember how good the Rams were,” Roderick said. “When I was at BYU, we had our butts handed to us. When I coached up the road at Utah we went there a few times and had some tough battles with that team. They’re a good program and I have a lot of respect for what it means to fans and the town.”

When BYU joined the Big 12 in 2023, the closest league opponent was Texas Tech (879 miles from Provo). The following season, Utah, Colorado, Arizona and Arizona State joined, and created a renewal of great regional rivalries.

The Cougars and Rams are scheduled to play in Provo in 2029 but, aside from future money games against Weber State and Southern Utah, there are no other regional nonconference games on the slate for BYU.

So both sides will savor Saturday’s meeting in Fort Collins, where the Cougars are a 17.5-point favorite.

Poppinga said, “These are battles. I think the guys are ready for this environment. It’ll be a sold-out crowd and loud. Their team is playing well, and their team has lot to cheer about.”

On Monday, Colorado State coach Jim Mora said, “It’s just that those (earlier) days, there was just a bit of an underdog feel (to BYU) and now they’re a powerhouse. They were a WAC team and now they’re a contender in the College Football Playoff.

“Quite frankly, it’s a bit of a road map for us here. Sticking with good people, doing the right things, making good decisions, continuing to elevate all areas of your program, which are the things that we’re doing here.”