Omak is located in the Mid-Valley area of the Okanogan Valley at the foot of the Okanogan Highlands. Approximately a quarter of the incorporated part of Omak lies in the Colville Indian Reservation. The Okanogan River meanders through the city of Omak on its way to the Columbia River. Crawfish Lake is located 15 miles (24 km) northeast of the town.
The town of Omak was platted in 1907, and officially incorporated on February 11, 1911. Shortly after being formed, the city of Omak waged a battle trying to get the county seat to be located there, but it lost to the nearby community of Okanogan.
Since 1933, Omak has hosted the World Famous Omak Stampede, with the Suicide Race added in 1935.