US borders to Mexico and Canada are closed until at least September 21. The borders have been closed since March 18.
We are relatively fortunate here in the US to have not one, but two international borders. Both Canada and Mexico present entirely different border crossings. Those of you in Asia, Europe, or Africa may not realize the differences.
The border crossing from Southern California into Mexico is relatively easy. It can be done on foot, since it is best to leave your car on the US side. Once past immigration, just take a cab into Mexico, usually Tijuana or the airport.
Coming back can be a hassle, particularly during shift changes and rush hour. Avoid the early morning and late evening rush caused by people who commute daily to and from Mexico to the US. The border guards generally look for large amounts of currency, firearms, and drugs. If you buy prescription drugs in Mexico, try to limit your supply to about 30 days.
The Canadian border, until recently, was always relatively hassle free. No problem at the international airports. But driving across is a real hassle. It seems our friends north of the border do not want us in Canada! When we crossed from Montana (Glacier National Park) into Canada (Waterton National Park), the border patrol (Canadian Mounties?) made us feel quite unwelcome.
“Why are you visiting? How long are you staying? Are you carrying and drugs or weapons?” The poor truck next to us was delayed for at least a half hour, and it was empty!!! And never, I repeat, never cross with a motor home, as it will be inspected in great detail for several hours, again for weapons and drugs.
Crossing from or into Canada via airports is much faster and friendlier. In fact, returning to the US is efficient and friendly since US Immigration performs the border check in Canadian airports instead of the Canadians. I have crossed in several places, Vancouver, Toronto, and Montreal with great efficiency both directions.
That said, we are all stuck at home. Personally, I would enjoy standing in a long line at customs and immigration, just for the fact that I am traveling again! 
Illegal immigration…crossing the border.
golfkat Travel Blog 
The experience is the reverse for Canadians driving into the US. It’s a hassle, but coming home to Canada is a welcoming breeze. By the way it’s Canada Border Services not the Mounties.
Thank you, I figured you are able to get back much easier than us. I was tongue in cheek about the Mounties, but thank you for the clarification.