Map for Gregg Boss Map for Gregg Boss Search | Advanced Search | New Members | Coupons and Discounts | All Categories To ensure the technician can contact you, please enter your email accurately and consider adding your phone number in the message body. Advertising & Media >> CSIA Certified >> Missouri Gregg Boss 820 St. Louis Ave.Valley Park, MO 63088 | directions (636) 225-3340 | fax: (636) 391-2786 Visit Site To ensure the technician can contact you, please enter your email address accurately and consider adding your phone number in the message body.