Where Is the Pacific–Mountain Boundary in Oregon?
Oregon's official two-zone split is defined by 49 CFR §71.9(a). From Idaho, the boundary follows the Baker–Malheur county line west to the northwest corner of Malheur County, then runs south along Malheur County's western boundary. It later turns east from the southwest corner of Township 35 South, Range 37 East to the Idaho border.
The practical result is simple but important: most of Malheur County is Mountain Time, while a southern portion remains Pacific Time. Ontario and Vale are on the Mountain side. Baker County, immediately west/northwest of the split, remains Pacific Time. Near the southern boundary, use an exact address or coordinates rather than assuming the entire county follows one clock.
Most OregonPacific Time · PST/PDT · America/Los_Angeles.
Most Malheur CountyMountain Time · MST/MDT · America/Boise.
Southern Malheur exceptionA portion south of the federal township boundary stays in Pacific Time.
Is Oregon Ending Daylight Saving Time?
No change is in force as of August 20, 2026. Current ORS 187.110 follows the federal standard time assigned to each Oregon area and advances the clock one hour from 2:00 a.m. on the second Sunday in March until 2:00 a.m. on the first Sunday in November. It also prevents Oregon cities and counties from adopting a different local standard of time.
Oregon enacted a 2019 conditional amendment that could make the Pacific Time portion of the state remain one hour ahead year-round after specified action in California and Washington. That condition has not been triggered. The statute notes a December 1, 2029 deadline for that 2019 mechanism. Separate 2025 proposals, including SB 1038 and SB 566, also did not replace the current seasonal schedule. Mountain Time Oregon remains under its normal MST/MDT cycle.
