I am assuming this marriage in Arnold's "Vital Record of Rhode Island" applies to this Levi, because he is identified as "Levi, of Nicholas." They were married by Samuel Wall, Justice. The Rhode Island Cemetery Database confirms these birth dates, and that they are both buried in West Greenwich Historical Cemetery #21.
Children
1. Captain Nicholas Whitford, b. 28 Jul 1773, West Greenwich, Kent Co., RI d. 8 Jan 1856 (Age 82 years)
2. Ezekiel Whitford, b. 2 Jan 1775 d. 15 Mar 1850 (Age 75 years)
The original birth entry reads: "Levi Whitford the First Son of Nicholas Whitford and Susanna His wife was Born October ye 21st Day 1753 the First Day of the week about 3 of the Clock in the morning"
Levi and Mary lived on Weaver Hill Road in West Greenwich, RI. The house and farm were in the Whitford family for nearly 100 years. The house is still standing and occupied. (See notes for his father Nicholas)
I have made an assumption that Levi and his wife both died in West Greenwich.