"Today, we're fighting a new war to defend our liberty and our people and our way of life," said Bush, standing in front of Washington's home and above a mostly frozen Potomac River.
"And as we work to advance the cause of freedom around the world, we remember that the father of our country believed that the freedoms we secured in our revolution were not meant for Americans alone."
Bush chose the national Presidents Day holiday to make his first visit as president to Mount Vernon. He and first lady Laura Bush helped lay a wreath at Washington's tomb, then the president gave a speech from a platform on the bowling green lawn of the estate.
"I feel right at home here. After all, this is the home of the first George W. I thank President Washington for welcoming us today. He doesn't look a day over 275 years old," Bush said to laughter.
Washington was born on Feb. 22, 1732.
"On the field of battle, Washington's forces were facing a mighty empire, and the odds against them were overwhelming. The ragged Continental Army lost more battles than it won, suffered waves of desertions, and stood on the brink of disaster many times. Yet George Washington's calm hand and determination kept the cause of independence and the principles of our Declaration alive," Bush said on a clear but frigid day, speaking to several hundred people.
Mount Vernon is about 16 miles south of the White House. Bush traveled by helicopter.
"In the end, General Washington understood that the Revolutionary War was a test of wills, and his will was unbreakable," said Bush. "After winning the war, Washington did what victorious leaders rarely did at the time. He voluntarily gave up power."
Washington's retirement didn't last long, Bush noted.
"As president, George Washington understood that his decisions would shape the future of our young nation and set precedent. He formed the first Cabinet, appointed the first judges, and issued the first veto.
"Over the centuries, America has succeeded because we have always tried to maintain the decency and the honor of our first president," Bush said.
Before and after Bush's speech, recorded music by the 3rd U.S. Infantry Old Guard Fife and Drum Corps blared through loudspeakers. Organizers of the event said the fife and drum corps had planned to perform live, but decided against it Sunday night because of expected temperatures in the 20s that could have damaged their historic instruments.