Thompson, from Sewickley, Pennsylvania, has captured four Senior Women's Amateur titles, two Mid-Amateurs and one Amateur. She won this event from 1999-2002, and moved a step closer to another crown by winning quarterfinal and semifinal matches on Wednesday at The Apawamis Club.
Thompson defeated Marianne Towersey, 3 and 2, in the quarterfinals and then got by Cecilia Mourgue D'Algue of France, 1-up, in the semifinals.
If she does win on Thursday, Thompson would equal the USGA record for titles owned by Joanne Gunderson Carner.
'Joanne and I played together as juniors and in a few U.S. Amateurs,' Thompson said. 'We've always been good friends.'
The 56-year-old Thompson had beaten Mourgue DAlgue in 19 holes in the final of this event in 1999.
It's a sharp contrast for the finalists. Thompson is playing in her 102nd USGA championship, while this is just the second for Lang, who resides in Weston, Florida, defeated defending champion Carolyn Creekmore, 1-up, in the quarterfinals and then disposed of Annette Gaiotti, 8 and 6, in the semifinals.
Earlier in the day, Gaiotti defeated Reggie Parker, 1-up, and Mourgue D'Algue got by Robin Donnelley on the 19th hole in the quarterfinals.