Krishnanagar is a district headquarters in Nadia, about 2.5 hours by train from Kolkata's Sealdah station. It is named after Raja Krishnachandra, the 18th-century king whose palace still stands in the town. The palace has historical significance but is not in great shape; it is worth a look.
The real reason to visit is Ghurni, a neighbourhood on the edge of town that has been a centre of clay sculpture for at least three centuries. The Patras — the families who carry on the craft — make astonishingly detailed and painted figures of gods, historical characters, and everyday Bengali life from the local clay. Several studios are open to visitors and sell finished pieces. The figures range from small affordable pieces to large commissions. Walking through Ghurni's lanes while craftsmen work is a genuinely interesting hour or two.
The bank of the Jalangi River is pleasant in the evening. Krishnanagar makes a good day trip from Kolkata or an overnight stop on the way to or from Nabadwip, which is just 15 km away.