02/27/2012 10:17 am ET Updated Feb 27, 2012

Illinois Early Voting Begins Monday (VIDEO)

Early voting in the March 20 Illinois primary election began Monday morning.

The early option runs until March 15 and allows registered voters to cast their ballots at 51 voting locations in Chicago, some 40 in the Cook County suburbs and more throughout the collar counties and the rest of the state. The city and suburban locations are open from 9 a.m. to 5 p.m. Monday through Saturday and many will also offer Sunday hours.

Cook County Clerk David Orr said that "you don't have to wait until March 20 to cast a vote in this election," the Associated Press reports.

Early voters are required to show a government-issued photo ID and can use any early voting location, regardless of where they live. The early ballots are considered final and voters are not allowed to change their ballot or attempt to vote more than once. Voters do not need to offer any reason or excuse to vote early.

The early voting process does, however, require that voters declare a party, as CBS Chicago reports.

Earlier this month, the number of registered voters in Chicago stood at an all-time low -- at least as far back as the records go: 1942. Officials have blamed the low-to-date numbers on the lack of a real contest for President Barack Obama as well as the primary being a "especially low-interest election" to many city voters.

Nevertheless, a number of heated congressional races will be decided by Illinois voters March 20. In the 2nd District, U.S. Rep. Jesse Jackson Jr. faces off against Democratic challenger, former one-term congresswoman Debbie Halvorson. In the 8th District, Democrats Tammy Duckworth and Raja Krishnamoorthi are both aiming for a green light to challenge controversial incumbent Republican U.S. Rep. Joe Walsh. And in the 16th District, two incumbent Republican Reps. -- Don Manzullo and Adam Kinzinger -- are going head to head.

U.S. Rep. Steve Israel of New York, who oversees the Democratic Congressional Campaign Committee, told the Associated Press that "Illinois offers one of the most dramatic playing fields" in the nation.

In Cook County, voters will also be considering Chicago Ald. Rick Munoz (22nd)'s challenge of incumbent Dorothy Brown for Clerk of the Cook County Circuit Court, as WBEZ reports.

In the 2008 presidential election, early voting attracted record crowds as more than 400,000 Chicago and suburban Cook County voters turned out.

If prospective voters missed the registration deadline, they may still register thanks to a "grace period" through March 13 at the election board's downtown headquarters.

WATCH Langdon Neal, chairman of the Chicago Board of Elections, comment on early voting -- a process he feels is too pricey:

Early Voting in Illinois Primary Opens in Cook County :