  Microlensing events have historically been discovered throughout the Galactic
bulge and plane by surveys designed solely for that purpose. We conduct the
first multi-year search for microlensing events on the Zwicky Transient
Facility (ZTF), an all-sky optical synoptic survey that observes the entire
visible Northern sky every few nights. We discover 60 high quality microlensing
events in the three years of ZTF-I using the bulk lightcurves in the ZTF Public
Data Release 5. 19 of our events are found outside of the Galactic plane ($|b|
\geq 15^\circ$), nearly doubling the number of previously discovered events in
the stellar halo from surveys pointed toward the Magellanic Clouds and the
Andromeda Galaxy. We also record 1,558 ongoing candidate events as potential
microlensing that can continue to be observed by ZTF-II for identification. The
scalable and computationally efficient methods developed in this work can be
applied to future synoptic surveys, such as the Vera C. Rubin Observatory's
Legacy Survey of Space and Time and the Nancy Grace Roman Space Telescope, as
they attempt to find microlensing events in even larger and deeper datasets.
