I am a UK resident and currently have a B1 visa with 7 years to run. When I enter the US via LAX they always stamp my passport and issue the I-94 card for 12 months. We always leave before the date given. Question - do we have to go back to the UK (our country of origin) or could we go to Canada for a week and then re-enter the US?
You can go to a third country, but your entry back into USA can be declined if CBP believes you are spending more time in USA than you should. Typically, B visas are for brief visits (may be six months or less in a 12-24 month period).