Town Hall Address 50 Billerica Road Chelmsford, MA 01824 United States- Middlesex County Website http://www.townofchelmsford.us/ Town Clerk 978-250-5205 http://www.townofchelmsford.us/235/Town-Clerk United States Assessor 978-250-5220 http://www.townofchelmsford.us/119/Assessors Mon-Fri: 8:30 to 4:00 50 Billerica Road Chelmsford, United States Tax Collector 978-250-5210 Mon-Fri: 8:30 to 4:00 50 Billerica Road Chelmsford, United States Fire District 978-250-5265 United States Water 978-250-5228 United States Town Hall Hours Mon-Fri: 8:30 to 4:00 County Middlesex