Halling & Cayo S.C. Legal Services Halling & Cayo S.C. Visit Website Request Info 320 E. Buffalo St. Suite 700 Milwaukee, WI 53202 414-271-3400 About Map About Halling & Cayo S.C. is a full service law firm headquartered in Milwaukee's Third Ward with additional offices in Pewaukee and Mequon. What's Nearby? Distance: 5 10 15 20 25 50 mi.