My spouse found our primary group through local Facebook searches. These homeschool groups are often called "co-ops" or "circles", but another good place is to check out your local parks, museums, family attractions like a zoo or activity center during what would be typical school hours. Engaging local parents that you see with what appear to be school aged children at these places (and I realize that can be awkward at times) is a good way to connect as well especially if your children are along.

EDIT: You can also check your local library, as the librarians are likely to know of at least one person who homeschools and might be able to connect you.