[4] The remains of a number of stilt house settlements from the neolithic until the late Bronze Age have been found along the lake shore in Nidau.

The triangular town pointed toward the castle and had a main street that paralleled the river and ran north–south.

[3] The last count of Nidau, Rudolf IV died in 1375 in a battle in the Gugler War.

In 1379, Count Rudolf von Kyburg sold the castle and town to the Habsburgs.

The Habsburgs then gave the castle as a fief to Enguerrand de Coucy, the former commander of the Guglers, in 1387.

During the Sempach War, in May 1388, Swiss Confederation forces from Bern and Solothurn attacked and besieged the town and castle for seven weeks before taking Nidau.

The castle was heavily damaged and the Swiss forces suffered heavy losses in the battle.

Its location on the Bern-Jura Mountains-Basel and the Geneva-Lake Constance roads as well as the shores of Lake Biel made Nidau into a natural transshipment point.

Most of the residents worked in the markets, ship building, goods transportation and hospitality.

Nidau converted to the new faith of the Protestant Reformation in 1528, along with the Canton of Bern.

Today the outer quarters developments of Nidau flow seamlessly into those of Biel.

Industry began to settle in Nidau in 1900, though today it is mostly home to small to medium businesses in the services sector.

Since the Jura water correction, the medieval centre and a good portion of the city of Nidau are now actually located on an island, created by the Nidau-Büren Aare canal, the river Thielle in French or Zihl in German, and the Lake Biel's shore.

[8] The blazon of the municipal coat of arms is Argent a Crayfish Gules and a Trout Azure dotted of the second.

[9] Nidau, located at the language boundary, although the official language is German, a high minority of French speakers live in the city, which has since long been offering them the right to send their children to the French-speaking schools of its sister city Biel/Bienne, the city of Nidau supporting the whole financial charge with its fiscal income.

[11] Most of the population (as of 2000[update]) speaks German (5,022 or 73.9%) as their first language, French is the second most common (1,071 or 15.8%) and Italian is the third (186 or 2.7%).

[16] The historical population is given in the following chart:[3][17][18] As of  2011[update], Nidau had an unemployment rate of 3.28%.

In the tertiary sector; 326 or 27.0% were in wholesale or retail sales or the repair of motor vehicles, 23 or 1.9% were in the movement and storage of goods, 112 or 9.3% were in a hotel or restaurant, 32 or 2.7% were in the information industry, 33 or 2.7% were the insurance or financial industry, 247 or 20.5% were technical professionals or scientists, 106 or 8.8% were in education and 185 or 15.3% were in health care.

[24] From the 2000 census[update], 3,637 or 53.5% belonged to the Swiss Reformed Church, while 1,503 or 22.1% were Roman Catholic.

This is followed by three years of obligatory lower Secondary school where the students are separated according to ability and aptitude.

Following the lower Secondary students may attend additional schooling or they may enter an apprenticeship.

The presence of the Nidau castle is first evidenced by a deed dated 30 August 1196, issued by Count Ulrich III of Neuchâtel.

[5] The last count of Nidau, Rudolf IV died in 1375 in a battle in the Gugler War.

In 1379, Count Rudolf von Kyburg sold the castle and town to the Habsburgs.

The Habsburgs then gave the castle as a fief to Enguerrand de Coucy, the former commander of the Guglers, in 1387.

During the Sempach War, in May 1388, Swiss Confederation forces from Bern and Solothurn attacked and besieged the town and castle for seven weeks before taking Nidau.

The castle was heavily damaged and the Swiss forces suffered heavy losses in the battle.

After the 1798 French invasion and the creation of the Helvetic Republic the old bailiwick was Nidau was dissolved.

The entire town of Nidau is part of the Inventory of Swiss Heritage Sites.

[31] Annually, on the last Saturday in May, the local Springtime festival "Stedtlifescht Nidau" takes place.