Rep. Mark Kirk (R-Ill.) and business consultant Dan Seals (D) are gearing up for the most expensive House race in the Chicago area this cycle — and it may turn into the most expensive race in the country that doesn’t involve a self-funder.

Both candidates are already trumpeting their second-quarter fundraising figures, even though they aren’t officially due to be released until July 15.

Early Monday afternoon, the Seals campaign announced it had raised more than $635,000 in the second quarter of the year ($2.1 million overall for the cycle) and will show $1.17 million on hand as of June 30. Those are impressive numbers for a challenger anywhere in the country.

Four hours later, Kirk released his fundraising figures, including $900,000 raised in second quarter ($3.87 million for the cycle) and $2.85 million in the bank.

Both candidates have more money at this point than they did in their 2006 match, when Kirk bested Seals 53 percent to 47 percent. The Congressman spent more than $3.5 million in the previous cycle, compared with almost $1.9 million for Seals. The Democratic Congressional Campaign Committee chipped in a mere $158,000, while the National Republican Congressional Committee sat the race out.

That election was overshadowed by very competitive and extremely expensive races in the neighboring 6th and 8th districts. But this year, the Kirk-Seals matchup will be the main event.

In the 6th district last cycle, state Sen. Peter Roskam (R) battled Iraq War veteran Tammy Duckworth (D) in an open-seat race that received national attention. Roskam spent $3.3 million and the NRCC almost $3.4 million compared with Duckworth, who spent more than $4.5 million, and the DCCC, an additional $3.2 million, in a race Roskam won 51 percent to 49 percent.

With Illinois Sen. Barack Obama (D) at the top of the ticket, Roskam can’t take anything for granted, but the race has not developed for the Democrats. Challenger Jill Morgenthaler (D) raised $307,000 through March 31 and had only $163,000 on hand. Roskam raised almost $1.4 million through the first quarter with $967,000 in the bank.

In the 8th district, Rep. Melissa Bean (D) spent almost $4.3 million last cycle in her successful re-election run, and the DCCC came in with about $1.3 million. Her opponent, wealthy businessman David McSweeney (R), spent $5.1 million (including primary spending), but the NRCC tacked on another $2.4 million. Bean won 51 percent to 44 percent.

This year, Republicans have another wealthy businessman running, Steve Greenberg, but it’s unclear how much he’s willing and able to invest in the race. He raised almost $523,000 through March 31 but had only $5,000 on hand. Bean raised more than $2.2 million through the first quarter with almost $1.4 million in the bank, and she is a heavy favorite for re-election.

Open-seat races in Illinois’ 11th and 18th districts will also get national party attention this year, and the 14th district rematch between new Rep. Bill Foster (D) and dairy magnate Jim Oberweis (R) could also be competitive.