Take highway 20 east from Bend to Burns, highway 78 from Burns east to the Fields-Denio road and then south to the desert and Steens Mountain.
Be careful approaching wet areas of the desert. It can look solid but sink you down or stick goo to your shoes. Early and late light give the most definition to the tiles.
The Alvord Desert lies to the east of Steens Mountain in the high desert area of southeastern Oregon. It is not large and is a very flat dry alkali lake bed. In the spring parts can flood and the drying process forms marvellous "tiles" and in some instances cracks. It is open to vehicular travel so it sometimes takes a little moving around to find an unspoiled area.