The Dark Energy Spectroscopic Instrument (DESI) cosmological survey, to be carried out on the 4m Mayall Telescope at Kitt Peak, uses baryon acoustic oscillations (BAO) and redshift space distortions (RSD) to study dark energy. The survey data will also lead to measurements of other cosmic probes as well as investigations of the physics of galaxies, quasars, and intergalactic gas. DESI will measure the BAOscalewith accuracies of better than 1% over a redshift range of 0<z<3. Galaxy peculiar velocities, as measured via RSD, can be used to test whether general relativity is correct on cosmological scales. Multiple DESI science working groups are targeting different science cases; the primary interests of the Argonne team are in the main dark energy probes as well as in the galaxy-halo connection, which provides cosmological information on much smaller length scales than BAO and (linear) RSD. eBOSS is the precursor survey to DESI, carried out using the SDSS telescope; results from Argonne’s trillion particle ‘Outer Rim’ cosmological simulation (carried out with HACC) have been used to make synthetic catalogs for both DESI and eBOSS.