The 2012 elections are officially underway, as candidates this week passed the deadline to qualify for the Aug. 28 primary election ballot. In Southern Arizona, some crowded races are taking shape.

The congressional, legislative and Pima County supervisors districts were redrawn since the last election cycle, because redistricting requires new districts with equal populations every 10 years. That means some politicians will face different voters this year.

Click here for new Legislative and Congressional district maps.

In Congressional District 2, Democrat Ron Barber and Republican Jesse Kelly qualified for the ballot. They are both seeking to fill the vacancy in Congressional District 8, which lasts until the end of the year.

To serve a full term, one of them would have to win election in the new District 2 in the fall. Barber will face state Rep. Matt Heinz in the primary, and Kelly will face a primary with Republicans Mark Koskiniemi and former CD8 candidate Martha McSally.

The race for U.S. Senate has been between high-profile candidates Republican Wil Cardon, Democrat Richard Carmona, and Republican U.S. Rep. Jeff Flake, but they won’t be the only ones on the ballot this year.

Tucsonan David Ruben is running against Carmona in the primary. Cardon and Flake will compete in a four-way primary with Bryan Hackbarth and Clair Van Steenwyk.

In the new Congressional District 3, incumbent Democrat Raúl Grijalva has a primary challenge from Democrats Amanda Aguirre, a former state representative, and Manny Arreguin.

In local races, all five Pima County supervisors face challengers. Topping the ticket is a four-way primary among Republicans hoping to take over District 1 from retiring Republican Ann Day. Ally Miller, Stuart McDaniel, Mike Hellon and state Rep. Vic Williams will compete for the party nomination. The winner will face former state Rep. Democrat Nancy Young Wright in the general election in November.

District 4 Supervisor Ray Carroll faces a primary challenge from Republican Sean Collins. In District 2, incumbent Democrat Ramón Valadez has a challenge from Republican James Kelley. District 3 incumbent Democrat Sharon Bronson will face Republican Tanner Bell, and District 5 incumbent Democrat Richard Elías has a challenge from Republican Fernando Gonzales.

Several legislative races are likely to be competitive, including the District 10 Senate race between Republican state Sen. Frank Antenori and former state Rep. David Bradley, a Democrat. The two face off in a district that is a mix of each of their former districts in midtown Tucson. In the same district, three Democrats and two Republicans are competing for the two House seats.

Other legislators will run unopposed this year unless challenged by a write-in candidate, including state Sen. Linda Lopez, a Democrat who will represent the new Legislative District 2. The same is true for Lynne Pancrazi, running for state Senate in District 4.

The full list of candidates qualified for the Aug. 28 primary election is posted on the Secretary of State’s website.