Size: L: 65 cm. Wt: 1150-2000g. Males and females similar. Breeding birds not seen on Great Lakes.

Winter: bill grey, appears slightly upturned; crown and nape dark grey; cheek and throat white, with clear demarcation between white and grey on head; breast white; eye red; back mottled grey and white, and darker than in Common Loon.

Juvenile: similar to winter adult.