Revenue Department 506 Main St Roundup, MT 59072 Phone : (406) 323-1513 Business Category Public Finance Taxation & Monetary Policy Montana State Of--revenue-field Office Roundup, MT 59072 Phone : (406) 323-1513 Business Category Government Offices-State Government Offices State & Local Government Offices & Public Schools Musselshell County Of--assessor Roundup, MT 59072 Phone : (406) 323-1513 Business Category Government Offices-County Government Offices & Public Schools Montana State Of--department Of Revenue, Roundup Field Office Roundup, MT 59072 Phone : (406) 323-1513 Business Category Government Offices-State Government Offices State & Local Government Offices & Public Schools