Gilliam County, Oregon was formed from Morrow and Wasco counties in 1885.
1890 Gilliam County, Oregon Census
- Free 1890 Census Form for your Research
- Hosted at Ancestry.com – Ancestry Free Trial
- Hosted at Census Guide
1900 Gilliam County, Oregon Census
- Free 1900 Census Form for your Research
- Free 1900 Census Images and Index
- Hosted at Ancestry.com – Ancestry Free Trial
- Hosted at Census Guide
1910 Gilliam County, Oregon Census
- Free 1910 Census Form for your Research
- Hosted at Ancestry.com – Ancestry Free Trial
- Hosted at Census Guide
1920 Gilliam County, Oregon Census
- Free 1920 Census Form for your Research
- Free 1920 Census Images and Index (partial)
- Hosted at Ancestry.com – Ancestry Free Trial
- Hosted at Census Guide
1930 Gilliam County, Oregon Census
- Free 1930 Census Form for your Research
- Hosted at Ancestry.com – Ancestry Free Trial
- Hosted at Census Guide