The 2015 winners were 3-0 up at half-time, scored four times in 10 minutes in the second half and then added six more goals in the last 16 minutes.
Alex Morgan scored five times for the United States with two goals apiece for Rose Lavelle and Samantha Mewis.
Lindsey Horan, Megan Rapinoe, Mallory Pugh and Carli Lloyd also scored to beat Germany’s 11-0 win over Argentina.
The United States’ previous biggest win in the tournament was a 7-0 success over Chinese Taipei in 1991, while Germany’s thrashing of Argentina came in 2007.
How the goals went in
1-0, 12 minutes: An unmarked Alex Morgan nodded in Kelley O’Hara’s cross.
2-0, 20 minutes: Rose Lavelle’s powerful strike was helped into the net by the keeper.
3-0, 31 minutes: Lindsey Horan scores from six yards out after Wilaiporn Boothduang fails to clear Tobin Heath’s free-kick.
4-0, 50 minutes: Samantha Mewis’ deflected effort gave her the 800th goal in Women’s World Cup history.
5-0, 52 minutes: Morgan tucked in after Thailand failed to clear a free-kick.