A year ago, four teams new to the Frozen Four experience made it to Pittsburgh.

With the tournament on the other side of Pennsylvania this year, it’s quite a different story.

The 2014 NCAA Frozen Four in Philadelphia will include three of the five most-frequently-appearing teams in Frozen Four history in Boston College (24, tied for first), Minnesota (21, tied for third) and North Dakota (20, fifth).

Union will join them, making its second appearance after a 2012 debut and looking for a first national title. The other three schools have combined for 17 of the 66 championships.

Boston College will play Union and Minnesota will play North Dakota in the semifinals on Thursday, April 10. The Eagles and Dutchmen will play at 5 p.m. EDT, with the Gophers and North Dakota following at 8:30.

One of the semifinals features teams that have played each other only once; the other is a meeting of longtime rivals.

The Eagles and Dutchmen played for the first time in the first round of last season’s NCAA tournament, with Union winning 5-1.

North Dakota and Minnesota have played 290 times since 1930, with the Gophers holding a 145-130-15 advantage in the series.

After they left the WCHA — Minnesota for the Big Ten, North Dakota for the NCHC — the teams weren’t scheduled to play this season for the first time since the 1946-47 season.

Instead, they’ll play in the NCAA tournament for the fifth time; each team has won twice.

Union is in the Frozen Four for the second time in the last three years after beating Vermont and Providence at the East Regional in Bridgeport, Conn.

The Dutchmen are 14-0-1 in their last 15 games, going unbeaten through February and March with a 62-25 scoring margin.

In Tampa, Fla., two years ago, the Dutchmen made their first Frozen Four appearance in just the school’s second time in the NCAA tournament. They lost to Ferris State in the semifinals.

The team that denied Ferris State a Frozen Four spot in double overtime in the Midwest Regional, North Dakota, is making its 20th trip to the national semifinals, fifth all-time behind Michigan, Boston College, Boston University and Minnesota.

After needing a Wisconsin win over Ohio State in the Big Ten tournament championship game just to get into the NCAA tournament, UND beat the Badgers and then Ferris State in Cincinnati.

In 10 seasons under coach Dave Hakstol, North Dakota is making its sixth trip to the semifinals. It has lost on the first day of the Frozen Four four of those times and lost the 2005 championship game to Denver.

With seven NCAA championships (its last in 2000), North Dakota is second only to Michigan all-time.

Boston College became the third team to clinch a spot in Philadelphia by beating Massachusetts-Lowell on Sunday after dispatching Denver a day earlier.

The Eagles have made it to the Frozen Four in every even-numbered year since 2004, winning the championship in 2008, 2010 and 2012.

This season, they had a 19-game unbeaten streak (17-0-2) but lost three of their last four games entering the NCAA tournament.

Boston College’s Hobey Baker Award favorite Johnny Gaudreau scored three times and added five assists in the Northeast Regional to improve his national-leading totals to 35 goals and 77 points.

Minnesota tied Boston University for third by clinching a 21st Frozen Four appearance after beating Robert Morris and St. Cloud State in the West Regional.

The Gophers were ranked No. 1 in the USCHO.com Division I men’s poll 17 times this season; they fell to second behind Union after losing in the Big Ten tournament semifinals.

Justin Kloos scored three times in the West Regional for Minnesota, giving him the team lead with 15 goals.

The Big Ten, ECAC Hockey, Hockey East and the NCHC each claimed one spot in the Frozen Four.