WILLIAMSBURG, May 18, 2014 (AFP) - The 24-year-old American finished 72 holes on 13-under-par 271 at the Kingsmill course.
Salas was coming off a missed cut two weeks ago at the North Texas Shootout.
Australian Sarah Jane Smith matched the low round of the day with a five-under 66 to finish second, her best LPGA finish.
She shared second place at 275 by American Lexi Thompson (69) and former world number one Tseng Ya-Ni (69).
South Korean Ryu So-Yeon (69) and New Zealand's Lydia Ko (71) shared fifth place at eight-under 276. Thidapa Suwannapura of Thailand shot two-under 69 to grab seventh at seven-under 277.
Last year's winner, American Cristie Kerr, stumbled to a one-over 72 for the second consecutive round. Kerr shared 29th place at two-under 282.
New Zealand teen Lydia Ko and American Stacy Lewis each missed a chance to move into the world number one ranking.
Leading scores on Sunday after the final round of the US LPGA Kingsmill Championship (USA unless noted, par-71):
271 - Lizette Salas 67-68-65-71
275 - Sarah Jane Smith (AUS) 68-71-70-66, Tseng Ya-Ni (TPE) 68-70-68-69, Lexi Thompson 67-69-70-69
276 - Ryu So-Yeon (KOR) 70-69-68-69, Lydia Ko (NZL) 70-68-67-71
277 - Thidapa Suwannapura (THA) 67-70-71-69
278 - Mina Harigae 72-68-70-68, Sandra Gal (GER) 69-71-69-69, Azahara Munoz (ESP) 65-71-72-70, Pornanong Phatlum (THA) 71-69-66-72
279 - Lee Mi-Hyang (KOR) 74-69-70-66, Jennifer Johnson 70-72-70-67, Suzann Pettersen (NOR) 72-68-70-69, Brittany Lang 67-68-74-70, Alejandra Llaneza (ITA) 68-69-71-71, Stacy Lewis 70-65-70-74
280 - Chie Arimura (JPN) 74-70-69-67, Joanna Klatten (FRA) 69-72-70-69, Charley Hull (ENG) 70-69-71-70, Austin Ernst 65-74-68-73, Katherine Kirk (AUS) 69-68-68-75
281 - Sarah Kemp (AUS) 70-71-72-68, Gerina Piller 69-68-75-69, Anna Nordqvist (SWE) 74-68-69-70, Paz Echeverria (CHI) 73-65-73-70, Mariajo Uribe (COL) 72-65-74-70, Lee Il-Hee (KOR) 72-70-68-71