The Manawatu 31-year-old brought up his double century in the 39th over from 126 balls as he and fellow opener Jeet Raval (115) put on a record-setting 321 for the first wicket.
The partnership was the highest for any wicket in domestic one-day history in New Zealand, while How's knock passed the previous highest score in a 50-over game in this country of 170 by Brendon McCullum for Otago against Auckland in 2008.
How was eventually out for 222 from 138 balls and his innings included 27 fours and eight sixes.
How's 222 equalled South African maestro Graeme Pollock's knock of 222 not out for East Province against Border in East London in 1974 in a 60-over game as the second-highest score in a List A fixture.
Today's innings from How marked only the 12th time a player has scored a double century in a List A game at domestic or international level worldwide.
The highest score in a List A game came in 2002 when Ali Brown made 268 from 160 balls for Surrey in a 50-over game against Glamorgan in England.
How had made only two previous centuries in 143 List A appearances prior to today's game, including 139 for New Zealand against England in a one-day international in Napier in 2008.
Central Districts finished on 417-6 from their 50 overs - the highest domestic one-day score in New Zealand - and Northern Districts will need a near-perfect performance to chase the total down.
At the Eden Park Outer Oval, Auckland were bowled out for 356 from 49.4 overs after Canterbury won the toss and put the home side in to bat.
Colin Munro (151) and Colin de Grandhomme (115) made hundreds for Auckland, while Canterbury seamer Matt Henry picked up 6-45 from 10 overs among the carnage.
In Invercargill, the game between Otago and Wellington started late due to rain but the home side won the toss and chose to bowl in a game that has been reduced to 39 overs per side.
