Minnesota is holding legislative and House primaries Tuesday. Here are the races to watch and why they matter.

1st Congressional District

Where: Runs from the Wisconsin to South Dakota borders across southern Minnesota, encompassing Mankato, Rochester and Winona.

Who: Former federal employee Jim Hagedorn has the Republican endorsement but is being challenged by business owner Steve Williams.

Why it matters: The winner faces Democratic Rep. Tim Walz. There is a possible rematch between Walz and Hagedorn.

• Full coverage: Election 2016

2nd Congressional District

Where: A district that stretches from Eagan past Wabasha covering many suburbs and exurbs.

Who: Four Republicans are vying for the chance to replace retiring Rep. John Kline. Ex-radio host Jason Lewis has the Republican endorsement. Business owner Darlene Miller has Kline's backing. Former state Sen. John Howe has the National Rifle Association on his side. Consultant and military vet Matthew Erickson is running on themes similar to Donald Trump.

Why it matters: This will be hotly contested fall campaign as the GOP looks to keep a seat Democrats believe they have a shot at. Former medical device company exec Angie Craig is the Democratic nominee and the Independence Party's Paula Overby is also on November's ballot.

4th Congressional District

Where: St. Paul and nearby suburbs to the north and east

Who: DFL Rep. Betty McCollum has a challenge from frequent candidate Steve Carlson. On the GOP side, plumbing company owner Greg Ryan carries the party endorsement into a matchup with property manager Gene Rechtzigel.

Why it matters: This has been a strongly DFL district for decades and barring a shocker will remain so.

5th Congressional District

Where: Minneapolis and nearby suburbs.

Who: DFL Rep. Keith Ellison faces a primary against two candidates, Lee Bauer and Gregg Iverson.

Why it matters: It's solid DFL district and Ellison has a growing national profile. His fall opponents in waiting are Republican Frank Drake and Legal Marijuana Now candidate Dennis Schuller.

6th Congressional District

Where: Central Minnesota from western and northern Twin Cities suburbs past St. Cloud.

Who: GOP Rep. Tom Emmer has two primary challengers in A.J. Kern and Patrick Munro. There are also three Democrats vying for their party's ballot slot: Judy Adams, Bob Helland and David Snyder, who has the DFL endorsement.

Why it matters: A reliably conservative district, Emmer is being challenged from his right and left.

7th Congressional District

Where: Most of western Minnesota.

Who: Amanda Hinson, an author and small business owner, and David Hughes, a pilot and Air Force veteran, are seeking the Republican nomination. Hughes has the party endorsement.

Why it matters: The winner will face longtime DFL Rep. Collin Peterson in a district the GOP would love to snatch now or after Peterson retires.

Secretary of State: Where to vote, how to register

Minnesota House of Representatives

Contested primaries in 14 House districts (10 DFL, 4 R).

1B (DFL), 6A (DFL), 7B (DFL), 13A (DFL), 15A (R), 31A (R), 31B (R), 40B (DFL), 48A (R), 50B (DFL), 56A (DFL), 59A (DFL), 60B (DFL), 65A (DFL).

House primaries of note:

• 6A: Four DFL candidates trying to fill open seat following retirement of Rep. Carly Melin, DFL-Hibbing

• 15A: Nine-term Rep. Sondra Erickson, R-Princeton, facing a challenge from Tom Heinks of Princeton, who claims he would be more fiscally conservative.

• 31A: House Speaker Kurt Daudt, R-Zimmerman, faces a challenge from Alan Duff of Isanti, who claims he would be more fiscally conservative. Outside groups spending money to criticize both candidates.

• 31B: Ten-term (nonconsecutive) Rep. Tom Hackbarth, R-Cedar, is trying to keep seat after losing the GOP endorsement to Calvin Bahr of East Bethel.

• 60B: Twenty-two-term incumbent Rep. Phyllis Kahn, DFL-Minneapolis, has two primary challengers: Mohamud Noor and Ilhan Omar. Both contend the demographically changing urban district needs new ideas. | Tuesday debate

• 65A: Rep. Rena Moran, DFL-St. Paul, is currently the only African-American member of the House. She's being challenged by Rashad Turner, a local leader of the Black Lives Matter movement.

Minnesota Senate

Contested primaries in 14 Senate districts (7 DFL, 7R).

1 (R and DFL), 5 (R), 15 (R and DFL), 23 (DFL), 24 (DFL), 27 (R), 32 (R), 52 (DFL), 53 (R), 59 (DFL), 62 (DFL), 64 (R).

Senate primaries of note:

• 1: There are two Republicans and two Democrats trying to fill the open seat after the retirement of Sen. LeRoy Stumpf, DFL-Plummer.

• 15: There are two Republican and two Democrats trying to fill the open seat after the retirement of Sen. David Brown, R-Becker.

• 32 Sen. Sean Nienow, R-Cambridge, is trying to keep seat after losing GOP endorsement to Mark Koran of North Branch.

• 59: Sen. Bobby Joe Champion, DFL-Minneapolis, is being challenged by Patwin Lawrence.

• 62: Sen. Jeff Hayden, DFL-Minneapolis, is facing a challenge from Mohamoud Hassan.

(Champion and Hayden are the only African-American members of the Senate. Both are facing voters for the first time since Republican filed ethics complaints against them.)

Minnesota Supreme Court

Incumbent Natalie Hudson faces two challengers, "attorney Craig Foss, who says he's running because he can't find a job, and attorney Michelle MacDonald, who ran an unsuccessful bid for the state's highest court in 2014 that MinnPost's Doug Grow called 'one of the most bizarre campaigns in state history,'" writes Greta Saul in MinnPost.

Correction (Aug. 9, 2016): Paula Overby's name was misspelled in an earlier version of this story. It has been corrected.