Bone fragments found near the wreckage of the plane flown by the adventurer Steve Fossett in the Sierra Nevada were confirmed to be his, officials said Monday.

A California forensics laboratory matched DNA found in the bones to that of Mr. Fossett, 63, who took off from a northern Nevada ranch in a two-seat light plane on Sept. 3, 2007, and never returned.

Hundreds of planes and searchers on foot scoured 17,000 square miles in the most extensive search for a missing aircraft in American history for signs of Mr. Fossett or the aircraft. Last month, a hiker in a remote area of the Inyo National Forest in east-central California came across some of Mr. Fossett’s belongings, leading searchers to the crashed plane. The bones that were tested were about a half-mile from the crash site, said Sheriff John P. Anderson of Madera County.

Image Steve Fossett in May 2006. Credit... Shawn Thew/European Pressphoto Agency

“What his family has wanted for over a year now, what his family has needed, is closure,” Sheriff Anderson said Monday in a statement.