QUINCY, Mass. – As Democratic Massachusetts Rep. William Delahunt formally announced his retirement Friday, state Republicans predicted they have one of their best shots in more than a decade at claiming a Bay State seat in the U.S. House of Representatives.

Currently, all of the state’s House members are Democrats, but Republicans are looking to take back Delahunt’s seat in the 10th District, which includes Cape Cod and the South Shore.

Republican U.S. Sen. Scott Brown won 61 percent of the vote in Delahunt’s district in a special election in January to fill the seat of the late Democratic Sen. Edward Kennedy.

“It’s the best district in the state for a potential Republican takeover,” said Jeffrey Berry, a political science professor at Tufts University.

“It has a disproportionately large elderly constituency, a little bit more Republican registration and orientation … there’s definitely a possibility for a takeover.”

Republicans planning to run for the seat include state Rep. Jeffrey Davis Perry of Sandwich and former state treasurer Joseph Malone.

Norfolk District Attorney William Keating, a Democrat, is also planning to run, as is state Sen. Robert O’Leary, a Democrat from Barnstable.

Michael Goldman, a political consultant advising Keating, said the Republicans will not have an easy time in the race.

“When we talk generically about government being too big and out of control, that’s an interesting message, but if they say they are not going to deliver for this district, they are not going to win,” said Goldman.

The last two Massachusetts Republicans to serve in Congress were Peter Torkildsen, who represented the 6th District, and Peter Blute, who represented the 3rd District. Both served two terms and lost re-election bids in 1996.