"Western Border" Is Not a Thing: Clarify Your Question

There is no single "Western Border." The term is meaningless without specifying whose western border.

Likely Candidates

• US Western Border: Pacific Ocean coastline (1,293 mi continental; + Alaska 6,640 mi)
• Canada Western Border: Pacific Ocean (15,000+ mi including islands) + Alaska land border (1,538 mi)
• Mexico Western Border: Pacific Ocean (4,500+ mi)
• European Countries' Western Borders: Atlantic Ocean (Portugal, Ireland, UK, France, Spain, Norway)
• US State Western Borders: Each of 50 states has one (e.g., California = Pacific, Colorado = Utah border)
• Historical: "Western Border" of Roman Empire (Rhine/Danube), US frontier (Mississippi → Rockies → Pacific)
• Idaho's Western Border: Washington (north) + Oregon (south) – ~300 mi total

How to Get Your Answer

1. Identify the entity (country, state, province, empire, property)
2. Specify which boundary (land, maritime, treaty-defined)
3. Ask: "What is the length/description of [Entity]'s western border?"

Context is everything. Resubmit with the specific jurisdiction.