Oletzko County
- This article should be merged with
Olecko
Oletzko County refers to historical East Prussia County with capital in Oletzko. The county was later renamed Treuburg.
- This article should be merged with
1818 - over 90% of population
1900 - 33.5% (Prussian census)
In 1888, Polish language was completely forbidden in the schools of all levels.
Population: 39.938 (1933) 38.046 (1939)