National Park Service officials said the Friday discovery on Lake Meredith was confirmed to be the fuselage of a small, two-seat Beech 77 that went missing during a two-hour flight on Jan. 27, 1984.
The 25-year-old pilot and a passenger died in the crash, according to a National Transportation Safety Board report.
In the first two days after the crash, one of the plane's wheels and a jacket believed to be the pilot's were found floating on the lake, the report said. The plane and bodies never turned up during a six-day diving search.
Park service personnel have closed the area around the wreckage so they can investigate the site, spokeswoman Rozanna Pfeiffer said in a news release.
Pfeiffer said Sunday more details might be released later in the day.
Lake Meredith, about 20 miles north of Amarillo, is at just 8 percent of its capacity of 500,000 acre-feet, according to the latest monthly report from the Texas Water Development Board.