- Machinery, Supplies & Equipment - Business Production Related, Janesville
- Machinery, Supplies & Equipment - Business Supplies Related, Janesville
- Machinery, Supplies & Equipment - Construction & Contractor Related, Janesville
- Mail Delivery Service, Janesville
- Manufacturing, Janesville
- Manufacturing Products, Janesville
- Masonry Contractors, Janesville - Stone Mason, Brick Mason - Install & Repair
- Meat Market, Wholesale & Products, Janesville
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- Metal Buildings, Janesville - Wood Buildings
- Metal Buildings, Janesville - Kits, Homes, Steel Buildings, etc
- Methodist Church, Janesville
- Miscellaneous Government, Janesville
- Miscellaneous Personal Services, Janesville
- Miscellaneous Photographers, Janesville
- Miscellaneous Professional, Janesville
- Motor Vehicle, Janesville
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