In 1839, the New Zealand Company signed an agreement with Ngāti Toa from which it claimed to have acquired the entire southern part of the North Island.

Following the signing of the Treaty of Waitangi, an inquiry by Land Claims Commissioner William Spain found that most of the alleged purchase, including Porirua, was invalid.

However, rising tensions with European settlers led to Ngāti Toa chief Te Rauparaha being captured by 200 British troops and police in July 1846.

Major territorial additions to the city occurred in 1973 and 1988 as part of the reduction and eventual abolition of Hutt County.

On 7 June 1976, New Zealand's first McDonald's restaurant opened in Porirua, on the corner of Cobham Court and Hagley Street.

During the following decade, Ashley Wallpapers developed the former UEB property and after favourable negotiations with the government, Todd Motors (later Mitsubishi) moved from Petone to Porirua.

The railway reached Longburn (south of Palmerston North) in 1886 to connect with the Government's lines to Taranaki and Napier.

With the acquisition of the company by the government in 1908, the line to Porirua and northward to Longburn became part of the North Island Main Trunk railway.

A shunting service from Wellington delivered goods wagons to sidings at Porirua, Paremata, Plimmerton, and Pukerua Bay and brought timber for the construction of houses in the area.

[29] On 24 July 1940, the line through Porirua, from Wellington to Paekākāriki, was electrified, and double track completed from Plimmerton to South Junction, just north of Muri railway station.

Electrification allowed the introduction of electric ED class locomotives, first introduced in 1938 for use on this line, to haul passenger and goods trains.

[28] The duplication of the line from Plimmerton to South Junction allowed a more frequent train service between Porirua and Paekākāriki.

Extension of the double track and automatic signalling continued with the Porirua to Mana section opened on 7 November 1960.

By 2016, the introduction of electric multiple units with more rapid acceleration, EM/ET class from 1982 and Matangi FP class from 2010, had reduced rail travel time for stopping trains between Wellington and Porirua by another 6 minutes to 21 minutes, despite extra stops at Redwood, Linden, and Kenepuru which each add 48 seconds to the travel time.

The Johnsonville bypass connecting the south end of the motorway to the top of Ngauranga Gorge opened about 1958, completing the four-lane road link between Wellington and Porirua.

The British Parliament passed the first New Zealand Constitution Act in 1846 which reformed the provinces and the Porirua area became part of New Ulster which now included all of the North Island.

The Hutt County covered all the area south of the Waikanae River and West of the Remutaka Ranges that lay outside of Wellington City.

Several suburbs without direct coastal access, including Aotea, Ascot Park and Ranui Heights, have substantial portions with good views over the harbour.

Much of the existing city centre, north of Parumoana Street and east of Titahi Bay Road, was built upon this landfill.

[53] Before North City and the Megacentre were built, shopping centred around the Cobham Court area of central Porirua.

State Highway 58 links Paremata via Whitby and Pāuatahanui (where an interchange with the Transmission Gully Motorway is located) with Haywards in the Hutt Valley to the east.

The railway stations from south to north are Kenepuru, Porirua, Paremata, Mana (known as Dolly Varden before 1960), Plimmerton, Pukerua Bay, and Muri (closed 30 April 2011).

Te Rauparaha Arena is a multi-purpose venue for sports and events located next to Pātaka Museum of Arts & Cultures.

Watersports, fishing and other boating activities are common in the area, served by a large marina in Mana and Sea Scouts, yachting, power-boating, rowing, and water-skiing clubs.

[63] As early as 1883, Porirua began to hold regular horse racing events on the harbour's Southern beach.

The Porirua Jockey Club was quickly established with Mr W. Jillett the first secretary and local butcher, John Rod, the treasurer.

Joshua Prosser built stables on his nearby property 'Prosser Block' (now Elsdon) and became a notable trainer of Dominion race-horses.

Porirua is also home to the three-time Chatham Cup winning Capital Football team Western Suburbs FC.

Well known as a dominant force in New Zealand club football, and for producing many former and current All Whites, they were officially recognised as Porirua City's 2006 Team of the Year for their Chatham Cup Grand Final triumph over Auckland's Eastern Suburbs.

A branch of Adrenalin Forest, an adventure park where paying visitors navigate rope bridges, swings and flying foxes strung between trees up to 31 metres off the ground, opened in Porirua in 2010.