It's difficult to definitively say which volcano in Auckland is the "oldest" because volcanic activity in the region occurred over a long period, and eruptions don't always happen in a clear, sequential order.

However, the oldest volcanic cones in Auckland are generally considered to be those in the Waitākere Ranges, which formed around 150,000 to 250,000 years ago. This is based on the age of the volcanic rocks in these cones.

Here's a breakdown of some important details:

* Waitākere Ranges: While they don't have the most recent volcanic activity, they are the oldest.

* North Shore: Some volcanoes on the North Shore, like Mount Eden and Mount Albert, are younger than the Waitākere Ranges but older than the volcanoes in the central Auckland isthmus.

* Central Auckland Isthmus: Volcanoes like One Tree Hill (Maungakiekie) and Rangitoto are some of the youngest in Auckland.

Therefore, while we can't definitively say which specific volcano is the absolute oldest, the Waitākere Ranges are generally considered the oldest volcanic region in Auckland.