Three longtime California Republicans announced their retirement from Congress this week in what amounts to a sort of exodus for the state's delegation as both parties adapt to a new, independently drawn congressional map in the country's most populous state.

Rep. Jerry Lewis, a 17-term incumbent, announced his retirement today, joining Reps. Wally Herger and Elton Gallegly, who announced earlier this week that they would not be seeking re-election.

"After months of consultation with loved ones and family, my wife Arlene and I have decided to retire from public life. We are deeply grateful to so many who have provided their support over the years," Lewis said in a statement.

The move by Lewis had been the subject of speculation for some time. He is a powerful appropriator and former chairman of the House Appropriations committee. Lewis and Gallegly are part of a sizable group of members from California's congressional delegation whose districts were carved up in the state's redistricting process, completed in the summer of 2011. Redistricting was conducted for the first time in California by a newly formed nonpartisan panel called the California Citizens Redistricting Commission.

Redistricting had previously been handled by state legislators and, as a result, partisan considerations were taken into account. This year, the aforementioned independent group took over the task of redistricting for the upcoming election. Because of this change, the state's congressional map was altered a great deal.

California is a state that has traditionally had a very stable delegation. In the past 10 years, only one district has seen a transfer of power from one party to the other. This year, however, the state will see a much different political narrative as a result of its newly drawn congressional district map.

"Before, all these people had safe districts and a lot of partisan influences were taken into consideration when drawing lines," Jessica Taylor, senior analyst at the Rothenberg Political Report, said. "With the commission who redrew the lines this year, they couldn't do that. "That's why you saw such a radically different map."

California is an important state for Democrats, who are hoping to take back the U.S. House.

"California was always going to be one of the Democrats best states," Taylor said. "In order to come close to taking back the House, they need to win at least five or six eats there."

Democratic Congressional Campaign Committee spokesman Jesse Ferguson put out a statement shortly after Lewis's announcement, citing "tea party extremism" as a cause for the growing list of Republican retirements.

"The tea party extremism of this dysfunctional Republican Congress is driving away independent voters and even pushing away its own Republican members" the statement reads. "House Republicans from California know they can't defend their extreme agenda to voters in 2012, and their mounting retirements create the latest Democratic opportunity that put the House in play."

Of course, the new map does not just affect California Republicans; many Democratic incumbents in the state will be facing primary challenges as a result of the newly defined districts.

Additionally, two incumbent Democrats - Reps. Dennis Cardoza and Lynn Woolsey- have so far announced their plans to retire at the end of the 112th Congress. An additional incumbent on the Democrats' side,  Rep. Bob Filner, is vacating his seat in order to run for Mayor of San Diego.

Rep. Pete Session, the chairman of the National Republican Congressional Committee- the Republican counterpart to the DCCC- put out a statement in which he thanked Rep. Lewis for his years of service, but did not reference the ensuing race in his district.

"As he concludes his service in Congress this year, I join Southern Californians in thanking him for over 30 years of leadership in working for a safer and more prosperous America" the statement reads.

The retirements of Republicans Lewis, Gallegly and Herger were not unexpected. Lewis is 77 and the longest-serving Republican member of Congress in California's history. Gallegly is 67 and also faced the prospect of a tough re-election as a result of redistricting. Herger is 66, although his district is still considered to be safe for Republicans.

The three have 43 terms - 86 years - of service among them.