The twentieth century up to the war

Less and less butter and cheese is made on the farms themselves. Mixed holdings appear, with arable farming alongside cattle.

A Boerenleenbank, a farmers' credit bank, is founded — now better known as a Raiffeisenbank.

The buildings of the Ons Belang cooperative — grinding, cattle feed and the like — go up on the Oude Nieuwveenseweg. They stand on the site where the sawmill of the firm J. Schoenmakers had been from 1846 to 1896.

The farmers of Nieuwveen begin using artificial fertiliser.

The Ons Belang cooperative, on the Oude Nieuwveenseweg since 1905, builds an extension.

The station building at Nieuwveen is built, to the Hesm I standard type.

Elim, the Johannes Stichting's annexe on the Kerkstraat where the women lived, burns down. There were no casualties.
After this fire men and women lived in a single building.

Market gardening begins along the Jaagpad by the Amstel: growing vegetables, at first in unheated ground.

Motorcycles, cars and lorries make their appearance in Nieuwveen too.

Opening of the railway connection between Uithoorn and Alphen aan den Rijn, with among others a station "Nieuwveen", at the end of what is now the W.P. Speelmanweg.
The original document gives 1916 as the year of opening and Amsterdam as the terminus; the line ran from Uithoorn to Alphen aan den Rijn and opened on 1 August 1915.
The line was 23 kilometres long and was built by the Hollandsche Electrische-Spoorweg-Maatschappij as part of the Haarlemmermeer railways. Because it mostly carried horticultural produce, it was popularly nicknamed "het bonenlijntje", the bean line.

The gemeenteraad abolishes the funfair, held from of old in the Kerkstraat.

The HESM opens a short goods branch from Nieuwveen to Papenveer. The station there is given the name of Ter Aar, two kilometres further on.

The steamboat services to Amsterdam and Leiden are discontinued. The Leiden firm De Volharding had run them since 1860.

The pumping station at Korteraar is converted from steam.

Electricity reaches Nieuwveen for the first time. Candles and paraffin lamps disappear; electric motors make their entrance.

The paraffin lanterns of 1867 give way to electric street lighting.

The gemeenteraad abolishes the cattle market in the Kerkstraat, held since 1828. Interest had already dwindled sharply around 1900.

A single fire pump with a petrol engine replaces the two hand pumps. It shifts 900 litres of water a minute.

A daily bus service to Alphen aan den Rijn and Leiden begins, set up by P. Langhout of Ter Aar.

G. Koppenol of Nieuwveen starts the first daily bus service to Amsterdam. On Fridays a service runs to Leiden, for those visiting the cattle market there.

The present Kattenbrug is built.
It replaced the wooden double-leaf drawbridge of 1823–1825. At this point Roovers gives 1824 as the year that wooden bridge was built, and 1823–1825 elsewhere.

The lower mill H of the Zevenhoven polder on the Ringdijk, built in 1810, disappears. What remains of it still stands and is in use as a house.

The office of mayor, shared from of old with Zevenhoven, is split. Nieuwveen gets J.W. Geesink; Zevenhoven, W.J. Boxce.

The Kerkstraat, until then surfaced with fine gravel, is the first road in the village to get a coat of road tar.

The first typewriter appears at the municipal office, an Underwood.

The Johannes Stichting expands with a second house, Sterrenberg at Huis ter Heide.

The tower of the Reformed church is altered.

The Ursuline sisters of Bergen are sent out to The Hague and Leiden to found boarding institutions there: Huize Angela and the Lidwinahuis.

Drinking water now comes from the mains, supplied by De Elf Gemeenten at Woerden. Rainwater and ditch water fall out of use.

Founding of the football club s.v. Nicolaas Boys, with a ground on what is now the W.P. Speelmanweg.

The country house Sassenoord on the Dorpsstraat, once founded by the Revd Pieter Schoenmakers, has been bought by the St. Joseph Stichting of Bergen (North Holland) and becomes a Roman Catholic residential institution for children with intellectual disabilities — geestelijk gestoorde kinderen, in the words of the day. The house is renamed Huize Sint Ursula.

The corn mill De Fortuijn on the Uiterbuurtweg, built in 1800, is demolished. With it the last mill in Nieuwveen disappears.

The office of mayor of Nieuwveen is merged with that of Rijnsaterwoude and Leimuiden. Mayor J.A. Bakhuizen, successor to J.W. Geesink, lives at Leimuiden and stays there. The arrangement did not go down well in Nieuwveen.

Closure of the railway connection Uithoorn – Alphen aan den Rijn, and with it the closure of Nieuwveen station.
The line had never paid its way from the outset. The station building of 1913 still stands and is now in use as office space, at W.P. Speelmanweg 39a.

The Raadhuis (town hall) on the A.H. Kooistrastraat is officially opened.