If You See a Baby Opossum it May Need Help Depending on the Size
Typically if you see baby wildlife the best rule of thumb is to leave them alone, but that's not always the case for opossums. Typically when it comes to wildlife if you see baby rabbits or a fawn, leave them alone (unless they are visibly in distress) because mama knows best. You can read more about how to check to make sure wildlife is okay, here.
However, when it comes to baby opossums if you see one alone depending on how big it is, it may actually need your help. I saw a post on Facebook recently, and I wasn't sure if it was true, turns out it is. The post said that sometimes baby opossums fall off mom and she doesn't realize it, leaving the baby stranded and in need of help. I decided to look that up and see if it's true and it is but under certain conditions. If you see a baby opossum by itself you'll want to measure it to see how big it is, that will tell you if it needs human intervention to help it.
According to HumaneSociety.org if you see a baby opossum that is more than 7 inches without including the tail, the baby is big enough to be on its own. However, if the opossum is less than 7 inches without including the tail, you'll need to contact a licensed wildlife rehabilitator.
While opossums get a bad rap for being a nuisance they're actually pretty cool animals! According to the Farmers Almanac opossums definitely don't deserve their bad reputation. They aren't rodents, they're actually North America's only marsupial. Opossums also eat ticks by the thousands, and they seem to have a real affinity for black-legged ticks like deer ticks which are known to spread Lyme Disease. Also, the Farmers Almanac says that opossums are typically pretty docile, they're unlikely to threaten pets or carry disease, not to mention they help with pest control. So the next time you come across an opossum, it's best to just leave it alone and let it continue on its pest-eating journey.