The lights on the U.S. Capitol Christmas Tree were lit during a ceremony held on Thursday, December 8, beginning at 5 p.m. on the West Front lawn of the Capitol. Architect of the Capitol Alan Hantman served as master of ceremonies. The Honorable Dennis Hastert, the Speaker of the House, pressed the switch lighting the tree at dusk.

The 2005 tree was from the Santa Fe National Forest, located in New Mexico. The tree was felled in early November and the 65-foot Engelmann spruce traveled on a trailer to Washington, D.C. It arrived at the Capitol on November 28. The tree was decorated with 3,000 ornaments crafted by the people of New Mexico that symbolize the state; large, globe-shaped ornaments; and 10,000 lights, which include strands of LED lights as part of the Capitol campus-wide effort to conserve energy.

The program featured holiday music played by a section of The United States Marine Band (The President's Own), and carols sung by the Congressional Chorus. Steven Castillo, an eight-year-old from Santa Fe, assisted Speaker Hastert with the lighting of the tree. His name was drawn from 5,000 names of New Mexico students who made ornaments for the tree. Members of the New Mexico Congressional delegation also attended.

The Christmas Tree has been a tradition at the U.S. Capitol since 1964. The tree was lit from dusk until 11 p.m. each evening through January 1, 2006.