What is the date of the closest passage to Earth of Comet Hale-Bopp?

Depending on whether you use the recent ESO Ephemeris, or the posted JPL date, it will happen on March 22-24 at a distance between 1.315 - 1.314 A.U. The closest distance to the Sun will happen on April 1 - 3 at 0.915-0.917 A.U. There are many web sites that have Hale Bopp data.