For the next several months, the battery was posted in New Orleans and for a time in Baton Rouge, taking a position in the defenses of that city during March.

[4] They returned to New Orleans on May 23, were resupplied with guns and were posted again as light artillery in the city defenses until October.

[4] During June and July 1863, two sections (consisting of four guns and roughly two-thirds of the enlisted men) took part in the Siege of Port Hudson though not heavily engaged.

[5] After the Confederates surrendered Port Hudson on July 9, the sections returned to New Orleans and the battery was reunited.

On October 15, the 12th Massachusetts battery moved to Port Hudson and would remain there on garrison duty until the end of their service.