Isaac Underhill Willets (December 7, 1819 – October 10, 1899) was a Long Islander and prominent farm owner best known today for the road named after him, I.U. Willets Road.
The road (in Western Nassau County) was built in 1850 through the middle of his lands. He complained that there were too many roads on Long Island to begin with. The road is known today as I.U. Willets Road. In Willets' time, the road was known as Westbury Road. When the Northern State Parkway opened in 1931, portions of I.U. Willets Road were closed to the public (the parkway cuts across the road). At its current Western end, just past the Parkway, lies Hollow Lane. This was also once part of I.U. Willets Road.map Portions of I.U. Willets Road were first paved in 1906. Today, the road that bears Willets' name runs through parts of North Hills, Manhasset Hills, Herricks, Searingtown, Albertson and Old Westbury. The Links (a gated housing development) and the Buckley Country Day School now occupy the land on what was Willets' property.
Willets was born to David Willets and Deborah Whitson in Westbury, New York. He married Mary Cromwell on December 29, 1843.