WASHINGTON -- He was born in the first term of Theodore Roosevelt, was first elected when Dwight Eisenhower was president and is retiring with the modern Republican party he helped form firmly in control. On Thursday, Sen. Strom Thurmond turned 100.

Thurmond spent his birthday on Capitol Hill, where for 48 years, longer than any senator in history, he has been an integral part of the changing political and racial mores of the South. In 1996, at age 93, he passed the late Sen. Theodore Green, D-R.I., to become the oldest person to ever serve in Congress. Green retired in 1960.

Thurmond, who resides at the Walter Reed Army Medical Center, arrived at his Senate office before noon as a snowstorm that swept through Washington abated.

"I am pleased to be celebrating my 100th birthday today," he said in a statement sent out by his office. "South Carolina is the finest state in our great nation and I am grateful to the people of South Carolina for allowing me this long and full career in public service. God bless the United States of America."

Several hundred people -- friends, family and Washington's elite -- were to honor the new centenarian at ceremonies in a Senate office building. Organizer Thad Strom, who worked for Thurmond for more than 20 years and is now a partner in a Washington consulting firm, said the speakers will include Sen. Trent Lott, R-Miss., the next Senate majority leader, and former Sen. Bob Dole, R-Kan.

He said eight of the nine Supreme Court justices -- all but Chief Justice William H. Rehnquist, who is recovering from knee surgery -- will attend, as will White House Chief of Staff Andrew Card and many of Thurmond's Senate colleagues.

In the western South Carolina town of Edgefield, where Thurmond was born on Dec. 5, 1902, and where he will return in January, people plan to gather around the life-sized Thurmond statue in the town square to celebrate with cake and performances from the Strom Thurmond High School band and chorus.

South Carolina Gov. Jim Hodges has declared Thursday Strom Thurmond Day, giving people in the state the occasion "to reflect on the many blessings he has bestowed upon our state throughout his life."

The state museum is to display Thurmond artifacts and the Strom Thurmond Institute of Government and Public Affairs at Clemson University is encouraging people to plant 100 trees across the state to honor the senator.

Thurmond is to be feted at the White House on Friday, and on Dec. 12 he is to attend ceremonies at Andrews Air Force Base outside Washington when the Air Force is to name its 100th C-17 cargo plane the "Spirit of Strom Thurmond."

President Bush, in a birthday message, noted that Thurmond, while serving as a circuit court judge, volunteered for combat duty during World War II and landed a glider at Normandy on D-Day at the age of 41. "His patriotism, courage and lifetime dedication to South Carolina and his nation will always be remembered," Bush said.

Thurmond is ending his eighth and final term a physically frail but still visible presence in the Senate. Generally confined to a wheelchair and always accompanied by aides during the last few years, he still rarely missed a Senate vote and his office maintained a reputation for constituent service. The man who entered the Senate abetting the body's deep racial division leaves it as a much-loved legend.

He is being succeeded by fellow Republican Rep. Lindsey Graham, who was born a year after Thurmond entered the Senate.

Thurmond won his first election to a local office in 1928, and, after serving in World War II, was elected governor in 1947. A year later he ran for president as a Dixiecrat, picking up 39 southern electoral votes as part of the South's states' rights rebellion against Harry Truman's civil rights policies.

In 1956, as a senator, he was an originator of the "Southern Manifesto" urging defiance of the 1954 Supreme Court desegregation ruling and in 1957 Thurmond talked against a civil rights bill on the Senate floor for more than 24 hours, the longest filibuster in Senate history.

Thurmond bolted the Democratic Party in 1964 to support GOP presidential candidate Barry Goldwater, signaling the beginning of the end of Democratic dominance in the South.

But Thurmond also changed with the times, in 1977 enrolling his six-year-old daughter in an integrated public school and becoming one of the first Southern lawmakers to hire black staffers and support blacks for federal judgeships.

During his Senate career he chaired both the Judiciary and Armed Services committees and has served as president pro tem, a ceremonial job that made him third in line to succeed the president.