Time in Oregon
Time in Oregon is divided into two zones. The vast majority of the state is contained in the Pacific Time Zone. Most of sparsely-populated Malheur County, including its largest city, Ontario, and its county seat, Vale, are in the Mountain Time Zone due to their proximity to Boise, Idaho. The time zone division occurs at the southwest corner of township 35 S, range 37 E (approximately 42.45 degrees north latitude), continuing east to the state line.
IANA time zone database 
In the IANA time zone database, Oregon is contained in two zones:
|c.c.*||coordinates*||TZ*||comments*||UTC offset||UTC offset DST||Note|
|US||+340308-1181434||America/Los_Angeles||Pacific Time||−08:00||UTC−07||All except northern 3/4 of Malheur County|
|US||+433649-1161209||America/Boise||Mountain Time - south Idaho & east Oregon||−07:00||UTC−06||Northern 3/4 of Malheur County only|