The date you closed the sale of your CA house is a very reasonable choice as your first day of being a resident of OR.
You have some flexibility in choosing the date you ceased being a CA resident and began to be an OR resident.
The date you choose as the first day of residency in a new state (or country) can also coincide with one of the following events:
- You or your spouse arrived in the new state or country
- Your belongings arrived
- You or your spouse started work
- You started renting your new place
- You purchased your new home
- You or a family member enrolled in school
- You or your spouse registered to vote
- You or your spouse applied for a state driver's license
