Picton is the small ferry port at the head of Queen Charlotte Sound, the northern entry point to the South Island. It is a town of fewer than 3,000 people that handles around a million ferry passengers a year, and most South Island road trips begin or end with the Interislander or Bluebridge sliding through the deep, sheltered water of the Sounds and tying up at the Picton wharf. The arrival is one of the great travel moments anywhere — three hours of forested fjord-like channels delivers you to a tidy waterfront town surrounded by hills.
Most travellers transit through in a couple of hours, which is a mistake. Picton is the gateway to the Marlborough Sounds — a maze of drowned valleys, peninsulas and islands that cover a fifth of the entire Marlborough region. The Queen Charlotte Track, a four-day coastal walk that you can sample as a single day, leaves directly from town by water taxi. The Edwin Fox — one of the oldest surviving merchant ships in the world, half-rebuilt in a dry dock at the wharf — is a properly atmospheric little museum that takes an hour.
The town itself is built around a horseshoe of sheltered foreshore. The promenade has cafes, a small aquarium, the i-Site, and several charter operators selling everything from sailing trips to dolphin swims. Behind the foreshore the streets climb steeply into hills covered in pine and gum trees; the Picton Lookout at the end of the Snout track gives the best wide view across the Sound.
For the Marlborough wine country, the town of Blenheim is half an hour south on State Highway 1 — the airport is also there. Stay a night in Picton at least if you possibly can; the place is a different town once the ferries stop running for the day.