Howdy Kayla,
I think you may be in luck

. It looks like the town of Boscawen NH, is about 30 miles away from you in Manchester, NH and there are historical references from the 1800's:
"Dr. Samuel Wood of Boscawen, an educator and a preacher, and well-known for his hobby the production of silk worms which fed on the leaves of the mulberry trees that grew in his back yard. At this fair, Dr. Wood was acknowledged the first person to plant the mulberry tree and to make silk in New Hampshire, and he received five dollars for a piece of finished material."
What you'll want to do is check-in with your local plant nursery business and see if they know where some are located nearby so that you can at least know what really big mulberry trees look like. Then wait until the leaves are actually being produced (May?) and start searching around the rest of your neighborhood. I must have driven by 2-3 of the half dozen that I located at least a hundred times before I realized that they were Mulberry trees! Elementary school playgrounds often have them. The schools used them for growing silkworms as class projects. I made a deal with the local elementary school that I would give them some silkworms and they would give me permission to pick their mulberry leaves

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