 The 1910 United States Census , before the city 's incorporation , recorded 520 residents . The following 1920 census — the first to define Omak as a distinct subdivision — counted 2 @,@ 500 residents , making it the most populous municipality of Okanogan County , having surpassed Okanogan ( 1 @,@ 519 residents ) . Subsequent census counts documented an increase to 4 @,@ 000 residents before a shrink in population at the 1980 census , when fruit prices rose , land was lost , and major employers were shut down . After this decline , the population steadily increased , approaching approximately 5 @,@ 000 residents by the 2000 census . Between 1990 and 2000 , the city 's population experienced a boom of 14 @.@ 7 percent , while between 2000 and 2010 , the population increased by around 2 @.@ 6 percent . The United States Census Bureau estimated that there were 4 @,@ 792 residents in 2013 , representing a 0 @.@ 6 percent increase over the 2010 census , while an estimate from Office of Federal Financial Management in 2013 documented a population decrease of 0 @.@ 3 percent to 4 @,@ 830 people . A 2011 study from the United States Census Bureau showed that there were 4 @,@ 881 residents , a 0 @.@ 7 percent increase over the 2010 census . 
