Oulainen (unofficially Swedish: Oulais) is a Finnish city located in the province of Northern Ostrobothnia, along the Ostrobothnian Railway and Main Road 86. The city has a population of 7,283 and an area of 597.54 km², of which 9.72 km² are water bodies. The population density is 12.39 inhabitants / km². The Pyhäjoki River flows through the city. The neighboring municipalities of Oulainen are Alavieska, Haapavesi, Merijärvi, Pyhäjoki, Raahe and Ylivieska.
Numerous signs of Stone Age settlement have been found
in the Oulainen region. At least the shores of Lake Piipsjärvi were
inhabited as early as the Stone Age. Among the numerous Stone Age
objects are e.g. Ostrobothnian axes, luck, East Karelian chisels,
spikes, slate rings and a spearhead made of black shale. On the
other hand, no definite finds have been made for the Bronze Age and
only one for the Iron Age. A bronze silver-plated horseshoe-shaped
buckle has been found in Matkanivan Männistö.
In the Middle Ages, Karelians and later people from Satakunta and Häme arrived in the region. The area was a border region, as the border of the Peace of Pähkinäsaari in 1323 probably crossed the region along the Pyhäjoki River. According to tradition, the first inhabitant of Oulainen would have been a Lappalainen named Oula, from which the name of the city would have been formed. More reliable information is available about the Savonian settlement that moved in the 15th century, from which time Oulainen has, for example, Savanlampi, the predecessor of the current Likalanjärvi name, or Savallampi. Documents from the beginning of the 16th century did not yet show the name Oulainen at all, but the area belonged to the extensive village of Matkaniva.
The first houses appearing in church records in the early 17th century, No. 1 Paavola (south of the river) and No. 2 Pyykölä (north of the river), were probably the first permanent inhabitants in Oulais. In 1608 there were 6 smokes in the village of Oulainen, which were taxed, and in 1682 there were 15 smokes. The nobles did not have manors in Oulais, although until 1674, when the provinces were to be returned to the state. The peasants mainly owned the Oulainen farm in the 18th century. According to a map from 1766, there were the following houses in the area of the current center of Oulainen: No. 1 Honka Paavola, No. 2 Pyykölä Isojussi, No. 3 Ranta Pyykölä, No. 4 Heickilä, No. 5 Jussila, No. 6 Pyy, No. 7 Anttila, No. 8 Pyykölä and No. 9 Miekkonen. The lands of these houses have become the center of what is now Oulainen.
The people of Oulu became Pyhäjoki Chapel Parish in 1682, when the first church was built. After the first small one, a new church was built in 1753. On February 16, 1757, the king granted Pyykölä Crown Estate No. 8 as the Kappainen's office building.
The first Oulainen road from Pyhäjoki to Haapavesi was completed in the late 18th century, but the Ylivieska road only in the 1860s. Railway traffic in Oulainen began after the completion of the Ostrobothnian line in 1886, when two stations were built: Oulainen station and Kilpua station.
From 1883 to 1902, the 13th reserve company operated in Oulainen, which was located on Niskanmäki on the former lands of Doubt, Konttila and farms. It originally included a total of 12 buildings and the number of people served there varied from 309 to 603 per year. Another large institution was the Oulainen sanatorium, which started in 1914 and treated patients with tuberculosis. The sanatorium was located partly in the former premises of the reserve company. The sanatorium was expanded in the 1930s and 1950s. Today, the sanatorium's facilities are partly used by the city and partly by Oulaskangas Hospital.
The good traffic location of Oulainen significantly contributed to the development of the Pyhäjoki Valley Center in the 20th century. Several large retail outlets were established in Kirkonkylä and industry, especially the sawmill industry, gradually emerged. The establishment of the Oulainen township came to the fore as early as 1949, but at that time the municipal council rejected the project, claiming that the church village area had already been formed into an urban community in 1925. Although the densely populated communities were abolished as early as 1955, Oulainen was not established as a township until 1967. Oulainen received city rights in 1977. Oulainen has also been a significant school town since the 1960s.