The DESI Legacy Imaging Surveys are a combination of three public projects
(the Dark Energy Camera Legacy Survey, the Beijing-Arizona Sky Survey, and the
Mayall z-band Legacy Survey) that will jointly image ~14,000 square degrees of
the extragalactic sky visible from the northern hemisphere in three optical
bands (g, r, and z) using telescopes at the Kitt Peak National Observatory and
the Cerro Tololo Inter-American Observatory. The combined survey footprint is
split into two contiguous areas by the Galactic plane. The optical imaging is
conducted using a unique strategy of dynamic observing that results in a survey
of nearly uniform depth. In addition to calibrated images, the project is
delivering an inference-based catalog which includes photometry from the grz
optical bands and from four mid-infrared bands (at 3.4um, 4.6um, 12um and 22um)
observed by the Wide-field Infrared Survey Explorer (WISE) satellite during its
full operational lifetime. The project plans two public data releases each
year. All the software used to generate the catalogs is also released with the
data. This paper provides an overview of the Legacy Surveys project.