Rep. Sonny Callahan, Alabama's senior congressman, has decided to retire after nearly 18 years in Washington.

The Republican was one of two congressmen who were announcing retirements Monday. The other is Rep. Robert A. Borski, a 10-term Democrat from Pennsylvania.

Callahan, 69, planned a news conference Monday evening in his hometown of Mobile.

Several Republicans speaking on the condition of anonymity said Callahan was notifying state officials of his plans. A longtime friend of the congressman said Callahan had tired of commuting from Mobile to Washington.

His decision means Alabama is losing at least two members of its seven-member House delegation. Rep. Bob Riley, also a Republican, is running for governor.

Callahan, a former trucking executive, was elected to the U.S. House in 1984 after serving in the Alabama Senate. From 1995-2001, he served as chairman of the House Appropriations subcommittee on foreign operations. Then he became chairman of the House Appropriations subcommittee on energy and water development, a key post for water projects in Alabama.

Callahan represents the First District, a predominantly Republican district that covers six counties in southwestern Alabama.

In Pennsylvania, Borski, 53, said he will retire at the end of his term rather than run against a fellow incumbent Democrat in a drastically redrawn district.

Borski, 53, has lived his entire life in northeast Philadelphia and said he doesn't know enough about the new district, carved out of the Republican-leaning suburbs of Montgomery County, to justify a run.

"I think I could win the general election ... but it would be a very difficult and time-consuming proposition," he said Sunday. He made his formal retirement announcement Monday.

Borski would have had to run against Rep. Joseph M. Hoeffel, whose base is in Montgomery County. Borski called the redistricting plan "immoral, if not unconstitutional," adding, "I think northeast Philadelphia has been disenfranchised."

Congressional districts had to be reconfigured to account for population changes reflected in the 2000 Census. Pennsylvania grew at a slower pace than any other state in the last decade and lost two of its 21 seats in the House.