Obiri, the 2023 New York winner, pulled away from compatriot Sharon Lokedi with just under a mile to go to cross in two hours, 19 minutes and 51 seconds.
Obiri's time obliterated the 22-year-old course record of 2hr 22min 31sec set by Kenya's Margaret Okayo in 2003.
Lokedi, the New York winner in 2022, finished second in 2:20:07 while last year's winner Sheila Chepkirui was third in 2:20:24.
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The top three finishers were all under Okayo's old course record.