  We have conducted a search for strong gravitational lensing systems in the
Dark Energy Spectroscopic Instrument (DESI) Legacy Imaging Surveys Data Release
9. This is the third paper in a series (following Huang et al. 2020; Huang et
al. 2021, Paper I & II, respectively). These surveys together cover $\sim$
19,000 deg$^2$ visible from the northern hemisphere, reaching a z-band AB
magnitude of $\sim$ 22.5. We use a deep residual neural network, trained on a
compilation of known lensing systems and candidates as well as non-lenses in
the same footprint. After applying our trained neural networks to the survey
data, we visually inspect and rank images with probabilities above a threshold.
We have found 1895 lens candidates. Out of these, 1512 are identified for the
first time. Combining the discoveries from this work, Paper I (335) and II
(1210), the total number of strong lens candidates from the Legacy Surveys that
we have discovered is 3057.
