SOUTHBOROUGH LOCAL NEWS & EVENTS, MA Feb. 15 is Southborough voter registration deadline By Community Advocate - February 2, 2012 26 FacebookTwitterEmail Click me to copy current URL Southborough – Voter registration deadline for the Presidential Primary is Wednesday, Feb. 15. The Town Clerk's Office will be open from 8 a.m. to 8 p.m. Feb. 15 is also the last day for a registered voter to change their political party.