Hunting the Most Distant Stars in the Milky Way

M giant stars offer our best opportunity to explore the outer reaches of the Galactic halo with today's modern wide-field surveys. While challenging to distinguish from the overwhelming number of nearby dwarf stars, when identified, M giants are powerful tracers of the structural and kinematic properties of the Milky Way's halo. Using optical and near-infrared photometry from the SDSS and UKIDSS surveys, we have collected a sample of 500 candidate M giants with estimated distances ranging from 30 to well over 200 kpc, spread over 4,000 sq. degrees. Our group has obtained spectroscopic observations on a fraction of these candidates, confirming the presence of M giants and measuring their radial velocities. We present our findings to date, which include the two most distant stars ever seen in the Milky Way, and discuss the implications of distant Milky Way stars on Λ-CDM formation models and mass estimates of the Milky Way. We gratefully acknowledge the support of NSF grants AST-1151462, AST-1109273 and AST-1255568.