The closure does not affect essential travel, such as crossing the border for work or for the transportation of goods. It does not affect supply chains.
When travelling for essential work into the U.S., there is no self-isolation requirement.
"Non-essential travel" includes tourism and travel that is recreational in nature, according to U.S. Homeland Security.
"Essential travel" includes critical infrastructure support, economic services and supply chains, health, immediate medical care, and safety and security.
U.S. citizens, permanent residents and those with valid travel documents are permitted to travel into the U.S. from Canada.